fbdev: metronomefb bugfix

This patch is a bugfix for the use of cfb_* functions instead of sys_*
functions.  sys_* should be used with vmalloced framebuffers.  the previous
cfb_ use would not work for callers of imageblit/etc.

Signed-off-by: Jaya Kumar <jayakumar.lkml@gmail.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>