qpnp-fg-gen3: expose a fake battery SOC for debug board

When a debug board is present, battery ID will be something like
7 Kohms. Expose a fake battery SOC when this is detected. This
will help avoiding the device shutdown if a low battery voltage
is seen by FG and state of charge goes to 0.

Change-Id: I750b2adfb00f12960f74bd552a5896f66ecaece6
Signed-off-by: Subbaraman Narayanamurthy <subbaram@codeaurora.org>