leds: leds-qpnp-flash: fix total current calculation

Total current in flash LED module use for battery and thermal
mitigation, in order to refactor currents for flash LEDs.
Total current is not adding flash LED1 current, and it leads
to wrong reference total current.

Also, update flash LED current mitigation calulations, in order
to prevent from operator precedence.

Change-Id: I5d685a60c02e0600e7ba6b23655430d21e853dbe
Signed-off-by: Jigarkumar Kishorkumar Zala <j_zala@codeaurora.org>