gpu: host1x: Skip redundant HW state update

gpu: host1x: Skip redundant HW state update

When the fence list is empty, host1x_intr_update_hw_state()
falls through to host1x_intr_disable_syncpt_intr()
which does two MMIO writes to disable the syncpoint
interrupt and clear its status.

The ISR has already disabled and acked the interrupt
before calling host1x_intr_handle_interrupt(), making
these two writes redundant. Skip the update_hw_state()
call if no fences remain.

Measured Syncpoint wait latency (50000 samples):
  Average latency:   10.6 us  -> 9.4 us
  99.99 pct latency: 51.90 us -> 36.58 us

Signed-off-by: Tanmay Patil <tanmayp@nvidia.com>
Acked-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Link: https://patch.msgid.link/20260514103153.766343-3-tanmayp@nvidia.com