media: vb2: unify calling of set_page_dirty_lock

Currently videobuf2-dma-sg checks for dma direction for
every single page and videobuf2-dc lacks any dma direction
checks and calls set_page_dirty_lock unconditionally.

Thus unify and align the invocations of set_page_dirty_lock
for videobuf2-dc, videobuf2-sg  memory allocators with
videobuf2-vmalloc, i.e. the pattern used in vmalloc has been
copied to dc and dma-sg.

Suggested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>