Fixes invalid shift
Fixes: g2m_left_shift_2.wmv
Found-by: Piotr Bandurski <ami_stuff@o2.pl>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
(cherry picked from commit 030c7f03)
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>