msm: limits: Add S1 supply current limiting driver for MSM8909

This driver is a current limit management module to help manage
instantaneous peak current drawn by multiple subsystems on shared
supply. The inputs to the mitigation algorithm are current states
of different subsystems sharing this supply like cpu frequency,
gpu frequency, number of cores online, soc temperature, core leakage,
and modem state. It throttles cpu frequency and limits number of
online cores to reduce the dynamic current so as to keep the total
current drawn from supply in safe limits.

Change-Id: I4592b8be48bad3709e8cfb09da53f23279a8ff9b
Signed-off-by: Manaf Meethalavalappu Pallikunhi <manafm@codeaurora.org>