[ALSA] hda: add PCM for 2nd ADC on ALC260

[ALSA] hda: add PCM for 2nd ADC on ALC260

Modules: HDA Codec driver

The following patch against alsa 1.0.11rc3 creates a PCM device (pcm1c) for
the second ADC present on the ALC260 codec used by the hda driver.  It also
defines a new mixer control allowing the mode of retasking pins to be set;
this means a user can (for example) designate the headphone jack to be a
second input. With this patch in place it is possible to do 4 channel
recording on laptops equipped with an ALC260 codec assuming both a stereo
line-in jack is provided in addition to a headphone jack.

Mixer controls are provided to allow the headphone jack to be switched as
an input.  In addition, an (input only) mode control is configured for
the line-in jack to allow a bias voltage to be requested (VREF80 or VREF50)
so headsets based on condensor microphones have a chance of working.

This patch has been tested on a Fujitsu S7020 laptop and as such these
features are currently only configured for the 'fujitsu' model.

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