leds: leds-qpnp: Set the strobe bit correctly for flash led

The strobe bit is set to 1 when the flash led uses HW strobe and it is
set to 0 when the flash led uses SW strobe.

CRs-Fixed: 585414
Change-Id: Id65e9e70bc6c84ca5c8a9e65fd86e67b513e6745
Signed-off-by: Abinaya P <abinayap@codeaurora.org>