power: qpnp-fg: reschedule update_sram_data only after first update

Currently, when the charging status changes and the last update
of SRAM parameters has been done before 5 seconds,
update_sram_data is rescheduled immediately. However that should
be allowed only after the first SRAM update completes. Fix it.

CRs-Fixed: 885280
Change-Id: Id8a6f72517422dd60fcce9a51f86ef245d59751a
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>