[PATCH] tdfxfb: Fix buffer overrun

The pseudo_palette has room only for 16 entries, but tdfxfb_setcolreg may
attempt to write more.

Coverity Bug 557

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