uvesafb: Really allow mtrr being 0, as documented and warn()ed

Fixup for commit "uvesafb: Clean up MTRR code"
    (63e28a7)

Signed-off-by: Sylvain "ythier" Hitier <sylvain.hitier@gmail.com>
Acked-by: Andy Lutomirski <luto@amacapital.net>
Also-spotted-by: Torsten Kaiser <just.for.lkml@googlemail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/video/uvesafb.c

@@ -1891,7 +1891,7 @@ static int uvesafb_setup(char *options)
 		}
 	}
 
-	if (mtrr != 3 && mtrr != 1)
+	if (mtrr != 3 && mtrr != 0)
 		pr_warn("uvesafb: mtrr should be set to 0 or 3; %d is unsupported", mtrr);
 
 	return 0;