power: supply: smblite: Add support for concurrency mode

Add an interface to enable/disable boost concurrency. When
enabled the charger in buck-mode can act as a boost over a
separate path. The feature is supported only on PM5100 and
can be enabled using "qcom,concurrency-mode-supported" flag.

Change-Id: I3ab78af2123add2c4d5cba96500e1576b3c7deb3
Signed-off-by: Ashish Chavan <ashichav@codeaurora.org>