drm/i915: silence rpm wakeref asserts on GEN11_GU_MISC_IIR access

Commit 8d9908e ("drm/i915/display: remove small micro-optimizations
in irq handling") not only removed the optimizations, it also enabled
wakeref asserts for the GEN11_GU_MISC_IIR access. Silence the asserts by
wrapping the access inside intel_display_rpm_assert_{block,unblock}().

Reported-by: "Jason A. Donenfeld" <Jason@zx2c4.com>
Closes: https://lore.kernel.org/r/aG0tWkfmxWtxl_xc@zx2c4.com
Fixes: 8d9908e ("drm/i915/display: remove small micro-optimizations in irq handling")
Cc: stable@vger.kernel.org # v6.13+
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Jouni Högander <jouni.hogander@intel.com>
Link: https://lore.kernel.org/r/20250805115656.832235-1-jani.nikula@intel.com
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
(cherry picked from commit cbd3bae)
Signed-off-by: Tvrtko Ursulin <tursulin@ursulin.net>

Author: jnikula

drivers/gpu/drm/i915/display/intel_display_irq.c

@@ -1506,10 +1506,14 @@ u32 gen11_gu_misc_irq_ack(struct intel_display *display, const u32 master_ctl)
 	if (!(master_ctl & GEN11_GU_MISC_IRQ))
 		return 0;
 
+	intel_display_rpm_assert_block(display);
+
 	iir = intel_de_read(display, GEN11_GU_MISC_IIR);
 	if (likely(iir))
 		intel_de_write(display, GEN11_GU_MISC_IIR, iir);
 
+	intel_display_rpm_assert_unblock(display);
+
 	return iir;
 }