ALSA: emu10k1: improve voice status display in /proc

ALSA: emu10k1: improve voice status display in /proc

Eliminate the MIDI type, as there is no such thing - the MPU401 port
doesn't have anything to do with voices.

For clarity, differentiate between regular and extra voices.

Don't atomize the enum into bits in the table display.

Simplify/optimize the storage.

Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
Link: https://lore.kernel.org/r/20230518140947.3725394-4-oswald.buddenhagen@gmx.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>