vc1: Use logical instead of bitwise or for coded_inter

This appears to be the intended behavior.
vc1: Use logical instead of bitwise or for twomv

CC: libav-stable@libav.org
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>
Signed-off-by: Tim Walker <tdskywalker@gmail.com>
fate: Add VC-1 interlaced twomv test

CC: libav-stable@libav.org