drm/i915: Fix irq related documentation

drm/i915: Fix irq related documentation

Also update the function names in the documentation.

Closes:
https://lore.kernel.org/intel-gfx/20241001134331.7b4d4ca5@canb.auug.org.au/

Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 3de5774cb8c0 ("drm/i915/irq: Rename suspend/resume functions")
Cc: Jonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Andi Shyti <andi.shyti@linux.intel.com>
Reviewed-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Reviewed-by: Krzysztof Karas <krzysztof.karas@intel.com>
Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241011214111.98128-1-rodrigo.vivi@intel.com
Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>