[media] s5p-fimc: Fix initialization for proper system suspend support

ST_LPM bit must not be initially set, so the first resume helper
call properly quiesce the device's operation.
Also fimc_runtime_suspend() at device remove is unneeded and
leads to unbalanced clock disable so remove it.

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>