ALSA: hda: make kobj_type structure constant

Since commit ee6d3dd4 ("driver core: make kobj_type constant.")
the driver core allows the usage of const struct kobj_type.

Take advantage of this to constify the structure definition to prevent
modification at runtime.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20230211-kobj_type-sound-v1-1-17107ceb25b7@weissschuh.net


Signed-off-by: Takashi Iwai <tiwai@suse.de>