video: fbdev: uvesafb: Remove redundant NULL check in uvesafb_remove

Because uvesafb_par is allocated as part of fb_info in uvesafb_probe,
so we don't need to do NULL check for both fb_info and uvesafb_par in
uvesafb_remove.

[ This patch also fix a warning report by fengguang.wu@intel.com
  "drivers/video/fbdev/uvesafb.c:1815 uvesafb_remove()
   warn: variable dereferenced before check 'par'" ]

Signed-off-by: Wang YanQing <udknight@gmail.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>