msm: krait-regualator: Use coefficients from device tree

The current driver assumes the coefficients and the number of phases
a platform supports.

Instead get these values from the device tree. This enables us to
support platforms with various coefficients for same phase counts.

Change-Id: I34f65de58fd30f92018db0f46137d22d9114b07e
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>