ALSA: usb-audio: Trim superfluous "MIDI" suffix from UMP EP name

ALSA: usb-audio: Trim superfluous "MIDI" suffix from UMP EP name

A single USB audio device may have multiple interfaces for different
purposes (e.g. audio, MIDI and HID), where the iInterface descriptor
of each interface may contain an own suffix, e.g. "MIDI" for a MIDI
interface.  as such a suffix is superfluous as a rawmidi and UMP
Endpoint name, this patch trims the superfluous "MIDI" suffix from the
name string.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-12-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>