drm: Reduce scope of 'state' variable

Smaller scope reduces visibility of variable and makes usage of
uninitialized variable less possible.

Changes in v2:
	- separate declaration and initialization
Changes in v3:
	- add missing signed-off-by tag

Signed-off-by: Dawid Kurek <dawikur@gmail.com>
Signed-off-by: Sean Paul <seanpaul@chromium.org>
Link: http://patchwork.freedesktop.org/patch/msgid/20170615174556.GA8872@gmail.com