ac/nir/ngg,radv: use intrinsic base for instance_rate_inputs check

ac/nir/ngg,radv: use intrinsic base for instance_rate_inputs check

radeonsi use packed location base while radv use un-packed location.
So we adjust instance_rate_inputs in each driver to hide the difference.
Note the attribute slot number is less than 16, so we can shift
instance_rate_inputs in radv by VERT_ATTRIB_GENERIC0 which is 16.

Reviewed-by: Timur Kristóf <timur.kristof@gmail.com>
Signed-off-by: Qiang Yu <yuq825@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/19868>