[media] exynos4-is: Remove meaningless test before bit setting

There is no need to check same bit before setting it, since we
always end up with a bit set. Remove some of the tests and make
set unconditional, in every place where all that needs to be done
is just setting a bit.

Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>