drm/panthor: Enable timestamp propagation

drm/panthor: Enable timestamp propagation

Set the GLB_COUNTER_EN bit to enable coherent propagation of GPU
timestamp values to shader cores. This is a prerequisite for exposing
device-coherent timestamp queries.

Bump the version to 1.6 so userspace can detect support.

v2:
- GLB_COUNTER_EN is not a toggle bit move to panthor_fw_update_reqs

Signed-off-by: Ashley Smith <ashley.smith@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Link: https://patch.msgid.link/20251127115019.2113040-1-ashley.smith@collabora.com
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>