msm: spm-regulator: Add support for ULT HF SMPS regulator

Add support for ULT HF SMPS regulator in spm regulator driver
ULT HF SMPS regulator is designed for PMIC chips with minimal
set of features to achieve better area efficiency.

Change-Id: I1001ef67b5b2facd3c00b3ae421a4f1e2779ae5d
Signed-off-by: Ashay Jaiswal <ashayj@codeaurora.org>