AIO cards offer at least four individual settings options with three
states each. Those settings are represented as two bits in the settings
register with the following meaning:

   0*some_base_bit --> Option value 0
   1*some_base_bit --> Option value 1
   2*some_base_bit --> Option value 2
   3*some_base_bit --> mask to select the two involved bits

This patch adds a generic ALSA control macro for such a value-to-bit
pattern mapping. It will be used in a later commit to expose four new
controls.
Signed-off-by: NAdrian Knoth <adi@drcomp.erfurt.thur.de>
Signed-off-by: NTakashi Iwai <tiwai@suse.de>