uvesafb: don't treat mode info retrieval failures as errors

Some BIOSes return error codes when queried for information about
modes from their own modelist.  uvesafb treats this as an error
case and bails out.

Change this behavior so that broken modes do not prevent the driver
from working.  Only the failure to retrieve information about any
usable video mode is considered to be an error case.

Signed-off-by: Michal Januszewski <spock@gentoo.org>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>