regulator: qcom_pm8008: Add LDO OCP interrupt support

When the load on an LDO is higher than what it can supply in the current
operational mode, the LDO can hit the OCP (Over Current Protection)
condition. Add interrupt support to notify the consumers about the OCP
condition so that the consumers can take the necessary action.

Note that mutex_lock() and mutex_unlock() in the original version
of this patch were replaced with regulator_lock() and
regulator_unlock() respectively to resolve a compilation error.

Change-Id: I118364ea0f5ea28e8749861136301c1c6b8d7f84
Signed-off-by: Kiran Gunda <kgunda@codeaurora.org>
Signed-off-by: David Collins <collinsd@codeaurora.org>