ALSA: hda - Fix inconsistent Mic mute LED

The current code for controlling mic mute LED in patch_sigmatel.c
blindly assumes that there is a single capture switch.  But, there can
be multiple multiple ones, and each of them flips the state, ended up
in an inconsistent state.

For fixing this problem, this patch adds kcontrol to be passed to the
hook function so that the callee can check which switch is being
accessed.  In stac_capture_led_hook(), the state is checked as a
bitmask, and turns on the LED when all capture switches are off.

Signed-off-by: Takashi Iwai <tiwai@suse.de>