drm/bochs: Move to tiny/

The bochs driver is only ~600 lines of code. Putting it into tiny/
cleans up the DRM directory slightly. Some style problems were fixed
and unneeded include statements were removed. No functional changes.

v2:
	* make bochs_mode_funcs static (Daniel, kernel test robot)
	* rebase onto aperture API changes

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20210702075434.27677-2-tzimmermann@suse.de