avcodec/texturedspenc: Fix invalid shift

Left shifts of signed types are UB unless the results fit
into the type. (Furthermore the value to be shifted need to be
nonnegative.)

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
This commit is contained in:
Andreas Rheinhardt 2022-05-10 18:00:56 +02:00
parent cf9e470d05
commit e92e74b897