platform: Fix timberdale dependencies

VIDEO_TIMBERDALE selects TIMB_DMA which itself depends on
MFD_TIMBERDALE, so VIDEO_TIMBERDALE should either select or depend on
MFD_TIMBERDALE as well. I chose to make it depend on it because I
think it makes more sense and it is consistent with what other options
are doing.

Adding a "|| HAS_IOMEM" to the TIMB_DMA dependencies silenced the
kconfig warning about unmet direct dependencies but it was wrong:
without MFD_TIMBERDALE, TIMB_DMA is useless as the driver has no
device to bind to.

Signed-off-by: Jean Delvare <jdelvare@suse.de>
Cc: Vinod Koul <vinod.koul@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Mauro Carvalho Chehab <m.chehab@samsung.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>