ALSA: hda-intel: Convert to RUNTIME_PM_OPS()

Use the newer RUNTIME_PM_OPS() macro instead of SET_RUNTIME_PM_OPS()
together with pm_ptr(), which allows us dropping ugly __maybe_unused
attributes.

This optimizes slightly	when CONFIG_PM is disabled, too.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20250313170731.26943-6-tiwai@suse.de