power: pm8921-bms: remove forcing shutdown soc

Forcing to return shutdown soc for the first 30 seconds was added so
that we show consistent soc right after bootup.

However with the recent changes to the algorithm viz. using termination
resistance for UUC, restricting UUC changes at most 1% and limiting the
OCV corrections, this forcing is not required. The soc stays within
limits of the shutdown soc.

Remove this forcing of shutdown soc.

Change-Id: Ie74e9318cca29ab60436df6ddec286917fbd0cd7
Signed-off-by: Abhijeet Dharmapurikar <adharmap@codeaurora.org>