drivers: thermal: Add support to change thermal zone configuration

Add debug file system node to configure the thermal zone parameters
dynamically. This node will use the same format that is used to print
the configuration of the thermal zone.

Change-Id: I4fd8cdafcb689f4d986738864e31177401f9bc47
Signed-off-by: Ram Chandrasekar <rkumbako@codeaurora.org>