v3d: Enable PIPE_CAP_PRIMITIVE_RESTART

v3d: Enable PIPE_CAP_PRIMITIVE_RESTART

We disabled PIPE_CAP_PRIMITIVE_RESTART on ffc4d82438d98 ("v3d: Disable
PIPE_CAP_PRIMITIVE_RESTART") because the HW can only support
PIPE_CAP_PRIMITIVE_RESTART_FIXED_INDEX subset.

But the introduction of PIPE_CAP_EMULATE_NONFIXED_PRIMITIVE_RESTART
allows us to support these nonfixed primitive restarts so we can now
re-enable NV_primitive_restart for OpenGL extensions.

Acked-By: Mike Blumenkrantz <michael.blumenkrantz@gmail.com>
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12669>