power: smb1360: Fix issue for safety-timer setting

Safety-timer means maximum duration in minutes that a single charge
cycle may last.
Fix issue by correcting the safety timer enable bit.

Change-Id: I2f4592bbb98360d80dd9210ed50b3cac83e137ae
Signed-off-by: Zhenhua Huang <zhenhuah@codeaurora.org>