drivers/video/uvesafb.c: fix error-path memory leak

Fix bug identified by Daniel Marjamki: `m' is leaked on the error path.

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=10452



Cc: Daniel Marjamki <danielm77@spray.se>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
Cc: "Randy.Dunlap" <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>