Add additional support for ISENSE and VSENSE feature for the TAS2562.
This feature monitors the output to the loud speaker attempts to
eliminate IR drop errors due to packaging.

This feature is defined in Section 8.4.5 IV Sense of the data sheet.
Signed-off-by: Dan Murphy <dmurphy@ti.com>
Link: https://lore.kernel.org/r/20200219134622.22066-1-dmurphy@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>