dt-bindings: qpnp-fg-gen4: support register with thermal core framework

Add support to register FG driver to register with thermal core
framework so that the battery temperature can be monitored by any
thermal governor and userspace is one of them.

Change-Id: Idfe7a2313330d01ceff3d205521939016376caed
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>