[PATCH] pnx4008:fix NULL dereference in rgbfb

Fix possible NULL dereference in pnxrgbfb.

Signed-off-by: Vitaly Wool <vwool@ru.mvista.com>
Cc: James Simmons <jsimmons@infradead.org>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>