p1022ds: add audclk hwconfig setting to enable codec reference clock

The Freescale P1022DS can use either a 12.288MHz or a 11.2896MHz reference
clock for the audio codec, but by default both are disabled.  Add a 'audclk'
hwconfig option that allows the user to choose which clock he wants.

The 12.288MHz clock allows the codec to use sampling rates of 16, 24, 32, 48,
64, and 96KHz.  The 11.2896 clock allows 14700, 22050, 29400, 44100, 58800, and
88200Hz.

Also configure a pin muxing to select some SSI signals, which will disable
I2C1.

Signed-off-by: Timur Tabi <timur@freescale.com>
Signed-off-by: Kumar Gala <galak@kernel.crashing.org>