power: smb1360: Add an optional property to stop updating empty_soc flag

By default, SOC empty irq triggers when voltage is less than empty_soc
threshold. Empty_soc flag will be set in irq handler and SOC reported
becomes 0%.

On some targets, while booting up at lower voltages, if the inrush
current is high, the voltage may momentarily drop below the empty_soc
threshold, falsely triggering the IRQ and setting the SOC to 0.
Make it optional to avoid this issue.

CRs-fixed: 713559
Change-Id: I30b1e4e88702bb9b3983f5a417c6897c767ddae6
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>