phy: Add USB HSIC PHY driver for Marvell MMP3 SoC

Add PHY driver for the HSICs found on Marvell MMP3 SoC. The driver is
rather straightforward -- the PHY essentially just needs to be enabled.

Signed-off-by: Lubomir Rintel <lkundrak@v3.sk>
Link: https://lore.kernel.org/r/20200925235828.228626-4-lkundrak@v3.sk


Signed-off-by: Vinod Koul <vkoul@kernel.org>