drm/i915: silence rpm wakeref asserts on GEN11_GU_MISC_IIR access

Commit 8d9908e8fe9c ("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" <[e-mail]>
Closes: https://lore.kernel.org/r/[e-mail]
Fixes: 8d9908e8fe9c ("drm/i915/display: remove small micro-optimizations in irq handling")
Cc: [e-mail] # v6.13+
Suggested-by: Ville Syrjälä <[e-mail]>
Reviewed-by: Jouni Högander <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jani Nikula <[e-mail]>
(cherry picked from commit cbd3baeffbc08052ce7dc53f11bf5524b4411056)
Signed-off-by: Tvrtko Ursulin <[e-mail]>

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

···
 	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;
 }