drivers: thermal: Snapshot of virtual sensor driver from msm-4.14

Add a snapshot of virtual sensor driver changes from msm-4.14.
This is snapshot as of 'commit <0a56f56a> ("drivers: thermal:
virtual-sensor: Add new virtual sensors for SDMMAGPIE")'.

Change-Id: Ic423883d207e1b7feb4e47aa57287a831b720994
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>