extcon: madera: Add support for Cirrus Logic Madera codecs

extcon: madera: Add support for Cirrus Logic Madera codecs

The Cirrus Logic Madera-class codecs include highly flexible support
for jack detection, accessory detection and accessory buttons.

Although the driver is very configurable, it is impossible to cover
in generic code every possible way in which the accessory detect block
could be used and every possible combination of external hardware. We
therefore provide enough configurability to cover all common cases but
we allow customers to provide custom replacements for some or all of
the detection state machine to provided added ability to handle unusual
hardware or applications without having to create a branched and modified
version of this driver.

Change-Id: Ibbef6dc9a5a139075daed8c1556698bfd8e6bb16
Signed-off-by: Richard Fitzgerald <rf@opensource.wolfsonmicro.com>
Signed-off-by: Stuart Henderson <stuarth@opensource.wolfsonmicro.com>