ALSA: seq: ump: Create UMP Endpoint port for broadcast

ALSA: seq: ump: Create UMP Endpoint port for broadcast

Create a sequencer port for broadcasting the all group inputs at the
port number 0.  This corresponds to a UMP Endpoint connection;
application can read all UMP events from this port no matter which
group the UMP packet belongs to.

Unlike seq ports for other UMP groups, a UMP Endpoint port has no
SND_SEQ_PORT_TYPE_MIDI_GENERIC bit, so that it won't be treated as a
normal MIDI 1.0 device from legacy applications.

The port is named as "MIDI 2.0" to align with representations on other
operation systems.

Reviewed-by: Jaroslav Kysela <perex@perex.cz>
Link: https://lore.kernel.org/r/20230523075358.9672-34-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>