staging: greybus: Constify gb_audio_module_type

staging: greybus: Constify gb_audio_module_type

Constify static struct kobj_type gb_audio_module_type to prevent
modification of data shared across many instances and to address the
checkpatch warning that "gb_audio_module_type" should be const. The
"gb_audio_module_type" struct is only used in one place:
err = kobject_init_and_add(&m->kobj, &gb_audio_module_type, NULL, ...
so checkpatch is correct that it can be made const.

Signed-off-by: Ayush Tiwari <ayushtiw0110@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@linaro.org>
Link: https://lore.kernel.org/r/ZfiQsZBrHfImIJfc@ayush-HP-Pavilion-Gaming-Laptop-15-ec0xxx
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>