ALSA: cs35l56: Add support for factory calibration

ALSA: cs35l56: Add support for factory calibration

Merge series from Richard Fitzgerald <rf@opensource.cirrus.com>:

Until now, all products with an amplifier supported by the cs35l56 driver
have shipped with Microsoft Windows pre-installed. The factory calibration
of speaker protection has therefore been done using the Windows driver.

However, products that ship with a Linux-based distro must be able to
perform the factory calibration procedure from within the Linux-based
environment. This patch series adds that support.

NOTE: unfortunately this is yet another series that is mainly ASoC but
also needs some changes to the HDA driver, and they have build dependencies
on the ASoC code. I suggest taking this all through Mark's tree and we'll
avoid sending any other commits to the HDA driver until it has all landed
in Takashi's tree.