ALSA: emu10k1: rename Audigy Analog Capture Boost control

Audigy has "Analog Capture Boost" mixer control,
however now this only controls mic level, not
other analog sources.

It applies also both to playback and capture,
so rename it to something more descriptive.

Signed-off-by: Maciej Szmigiero <mail@maciej.szmigiero.name>
Signed-off-by: Takashi Iwai <tiwai@suse.de>