drm : Insert blank lines after declarations.

Resolve checkpatch issues for missing blank lines after declarations.
Issues found in multiple files with checkpatch.pl.

Signed-off-by: Suraj Upadhyay <usuraj35@gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20200702131749.GA25710@blackclown