power: qpnp-smbcharger: support flash icl loop disable workaround

Support setting the FLASH_TRIGGER power supply property in order to
disable the input current limit regulation loop when flash is strobing
without OTG connected.

Change-Id: I8d8dba8050a3fe066bbea108e4aaafda6045123b
Signed-off-by: Xiaozhe Shi <xiaozhes@codeaurora.org>