usb: gadget: midi2: More flexible MIDI 1.0 configuration

usb: gadget: midi2: More flexible MIDI 1.0 configuration

This patch allows users to set up MIDI 1.0 ports more flexibly.
Namely, instead of the fixed mapping only from FB 0, now multiple
block definitions are applied to build up the MIDI 1.0 mapping.

The each block config has midi1_first_group and midi1_num_groups
attributes, and those specify which Groups are used for MIDI 1.0.
Those fields must be within the UMP Groups defined in the block
itself.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20230725062206.9674-8-tiwai@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>