ext/alsa/gstalsamixer.c: If there's no mixer track by the name of 'Master' or 'Front', check if there's one called 'P...

Original commit message from CVS:
Patch by: Jerone Young <jerone at gmail com>
* ext/alsa/gstalsamixer.c: (gst_alsa_mixer_find_master_mixer):
If there's no mixer track by the name of 'Master' or 'Front',
check if there's one called 'PCM' before trying the generic
fallback logic (fixes #506928, where we pick 'Mic' as master
track for the AD1984 card in a Thinkpad T61/X61 laptop).