ps3fb: default to 480p on DVI-D/HDMI if video=safe

Default to the 480p video mode on DVI-D and HDMI displays if `video=safe' is
passed on the kernel command line.

This is intended to be used by `kboot'-style boot loaders (i.e. first-stage
kernels) for the PS3, to provide a failsafe video mode.

Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>