power: vm-bms: Disable FIFO update irq before forcing S3

FIFO update irq must trigger when BMS in S2 state, to avoid
a race between switching BMS states and FIFO update, we should
disable this irq before forcing S3 in suspend and enable it
after forcing S2 in resume.

Change-Id: I1c31f8b88ac9a9d3af9646075be4d9e22a105144
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>