video: Remove set but not used variable

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/video/fbdev/sis/300vtbl.h:1064:28: warning:
‘SiS300_CHTVVCLKSONTSC’ defined but not used [-Wunused-const-variable=]

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Li Heng <liheng40@huawei.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1600957106-13741-1-git-send-email-liheng40@huawei.com

video: move fbdev to drivers/video/fbdev

The drivers/video directory is a mess. It contains generic video related
files, directories for backlight, console, linux logo, lots of fbdev
device drivers, fbdev framework files.

Make some order into the chaos by creating drivers/video/fbdev
directory, and move all fbdev related files there.

No functionality is changed, although I guess it is possible that some
subtle Makefile build order related issue could be created by this
patch.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Acked-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Rob Clark <robdclark@gmail.com>
Acked-by: Jingoo Han <jg1.han@samsung.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>