drivers: thermal: Add support to scale ibat current using range factor

Add support to read ibat range factor from nvmem and use it to
scale ibat current for greater than default max supported
ibat range.

Change-Id: Iee83be8d6663920d4df0b792417820d222e3ff46
Signed-off-by: Gopala Krishna Nuthaki <gnuthaki@codeaurora.org>