vt: fix background color on line feed, DEC invert

Original report: """I used to force my console to black-on-white by the
command `setterm -inversescreen on`.  In 2.6.26-rc4, I get lots of black
background characters."""

Another addendum to commit c9e587ab.  This was previously missed out since
I was not aware of what vc_decscnm was for.
Signed-off-by: Jan Engelhardt <jengelh@medozas.de>
Reported-by: <thunder7@xs4all.nl>
Tested-by: <thunder7@xs4all.nl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/char/vt.c

@@ -434,7 +434,7 @@ static void update_attr(struct vc_data *vc)
 	              vc->vc_blink, vc->vc_underline,
 	              vc->vc_reverse ^ vc->vc_decscnm, vc->vc_italic);
 	vc->vc_video_erase_char = (build_attr(vc, vc->vc_color, 1, vc->vc_blink, 0, vc->vc_decscnm, 0) << 8) | ' ';
-	vc->vc_scrl_erase_char = (build_attr(vc, vc->vc_def_color, 1, false, false, false, false) << 8) | ' ';
+	vc->vc_scrl_erase_char = (build_attr(vc, vc->vc_def_color, 1, false, false, vc->vc_decscnm, false) << 8) | ' ';
 }
 
 /* Note: inverting the screen twice should revert to the original state */