[ALSA] sound/pci: remove duplicated defines

Remove duplicated defines.
(From their use it looks like 'midiDataOutx are written to
rather than read from.)

Signed-off-by: Nicolas Kaiser <nikai@nikai.net>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@perex.cz>