media: mmp-driver: add needed __iomem marks to power_regs

Solve those warnings:

    drivers/media/platform/marvell-ccic/mmp-driver.c:135:41: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:135:41:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:135:41:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:136:44: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:136:44:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:136:44:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:174:38: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:174:38:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:174:38:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:175:38: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:175:38:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:175:38:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:195:48: warning: incorrect type in argument 1 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:195:48:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:195:48:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:196:55: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:196:55:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:196:55:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:197:54: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:197:54:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:197:54:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:202:48: warning: incorrect type in argument 1 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:202:48:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:202:48:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:203:55: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:203:55:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:203:55:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:204:54: warning: incorrect type in argument 2 (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:204:54:    expected void [noderef] <asn:2>*<noident>
    drivers/media/platform/marvell-ccic/mmp-driver.c:204:54:    got void *
    drivers/media/platform/marvell-ccic/mmp-driver.c:389:25: warning: incorrect type in assignment (different address spaces)
    drivers/media/platform/marvell-ccic/mmp-driver.c:389:25:    expected void *power_regs
    drivers/media/platform/marvell-ccic/mmp-driver.c:389:25:    got void [noderef] <asn:2>*

Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>