usb: gadget: midi2: Fix incorrect default MIDI2 protocol setup

commit 3eb27d3e upstream.

The MIDI2 gadget driver handled the default MIDI protocol version
incorrectly due to the confusion of the protocol version passed via
configfs (either 1 or 2) and UMP protocol bits (0x100 / 0x200).
As a consequence, the default protocol always resulted in MIDI1.

This patch addresses the misunderstanding of the protocol handling.

Fixes: 29ee7a4d

 ("usb: gadget: midi2: Add configfs support")
Cc: stable <stable@kernel.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://lore.kernel.org/r/20240708095719.25627-1-tiwai@suse.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>