target/hexagon: add GVec overrides for HVX vector average Reviewed-by: Marco Liebel <marco.liebel@oss.qualcomm.com> Link: https://lore.kernel.org/qemu-devel/20260807152241.1576334-6-brian.cain@oss.qualcomm.com Signed-off-by: Brian Cain <brian.cain@oss.qualcomm.com>