ASoC: twl6040: Handle handsfree overcurrent events

TWL6040 has a short circuit detection mechanism that report events
when the current exceeds 2.2A in its handsfree output stage. Upon
detection of handsfree overcurrent, the suggested action is to
disable handsfree drivers to prevent damage. Additionally, when
this event occurs it's reported to Android userspace layers through
an uEvent associated with the TWL6040 MFD.

Change-Id: Iea94c55286a9adb158caac10f7a15fae73827792
Signed-off-by: Misael Lopez Cruz <misael.lopez@ti.com>
Signed-off-by: Chris Kelly <c-kelly@ti.com>

Conflicts:
	sound/soc/codecs/twl6040.c