[PATCH] vesafb: Fix return code of vesafb_setcolreg

If the hardware palette cannot be accessed, make vesafb_setcolreg return a
nonzero value.

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