media: imx355: Use v4l2_link_freq_to_bitmap helper

Use the v4l2_link_freq_to_bitmap() helper to figure out which
driver-supported link freq can be used on a given system.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>