power: vm-bms: fix battery resistance incorrect issue

Battery profiling should contain a table of battery resistance
vs PC(Percentage Charge).
If we use SOC to look up battery resistance, it'll get a
very high value when battery OCV is around 3.4V. Fix this
by using PC instead.

Change-Id: Id96b551ee2c83bd7560313c99c8de378e2b31982
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>