ALSA: hda: cirrus: Add initial DSP support and firmware loading

Merge series from Vitaly Rodionov <vitalyr@opensource.cirrus.com>:

The CS35L41 Amplifier contains a DSP, capable of running firmware.
The firmware can run algorithms such as Speaker Protection, to ensure
that playback at high gains do not harm the speakers.  This exports some
interfaces to allow more use of this DSP by the HDA version of the driver.