[media] s5k5baf: fix sparse warnings

drivers/media/i2c/s5k5baf.c:1796:33: warning: duplicate const
drivers/media/i2c/s5k5baf.c:379:24: warning: cast to restricted __le16
drivers/media/i2c/s5k5baf.c:437:11: warning: incorrect type in assignment (different base types)
drivers/media/i2c/s5k5baf.c:445:16: warning: incorrect type in return expression (different base types)

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>