[PATCH] fbdev: fix framebuffer memory calculation for vesafb

[PATCH] fbdev: fix framebuffer memory calculation for vesafb

- use vesafb_fix.line_length * vesafb_defined.yres to calculate the minimum
  memory required for a video mode. From Aurelien Jacobs <aurel@gnuage.org>.

- separately calculate the memory required for a video mode, memory to be
  remapped, and total memory (for MTRR). From Gerd Knorr
  <kraxel@bytesex.org>.

- the 'vram' option is for memory to be remapped, not total memory.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>