VT notifier fix for VT switch

VT notifier callbacks need to be aware of console switches.  This is already
partially done from console_callback(), but at that time fg_console, cursor
positions, etc.  are not yet updated and hence screen readers fetch the old
values.

This adds an update notify after all of the values are updated in
redraw_screen(vc, 1).

Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>