drm/i915/irq: Improve error logging for unexpected DE Misc interrupts

Dump the iir value in hex when the interrupt is unexpected.

Link: https://gitlab.freedesktop.org/drm/intel/-/issues/9652#note_2178501


Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Rahul Rameshbabu <sergeantsagara@protonmail.com>
Reviewed-by: Chaitanya Kumar Borah <chaitanya.kumar.borah@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231126214142.102106-1-sergeantsagara@protonmail.com