media: platform: Improve getting and requesting irq flow for bug fixing

Delete platform_get_resource operation for irq.
Return actual value rather than EINVAL when fail to get and request
irq.

Reviewed-by: Tomasz Figa <tfiga@chromium.org>
Signed-off-by: Xia Jiang <xia.jiang@mediatek.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>