msm: camera: Configure LED's independently

There are two LED sources on msm8974 fluid and mtp. On earlier
version of pmic, both LED had to be configured by same led trigger
client. On latest version, both LED's can be configured independently.
Store number of LED sources and use individual client to configure it.

Use flash torch property for torch mode
For 8974 fluid, pm8941 2A torch is attached to S5K3L1YX sensor.
Add LED torch source in device node. Sensor device nodes parse
torch source properties in sensor driver.

Change-Id: If1912ea2eff39c6832885e8a3c51e91c20ea0dcc
Signed-off-by: Sreesudhan Ramakrish Ramkumar <srramku@codeaurora.org>
Signed-off-by: Evgeniy Borisov <eborisov@codeaurora.org>