power: qpnp-bms: clean up rbatt logs

Currently, the BMS tries to loop through 0 to 100 SoC in order to
find a termination UUC. However, it calls get_rbatt once per loop.
The get_rbatt function prints multiple debug messages per call.
This generates a huge amount of logs, making debugging difficult.

Fix this by getting rid of the debug messages in get_rbatt and
printing the final rbatt after the loop.

Change-Id: I077e44065395d7e82c63415a2328c6983cddf3b9
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>