ARM: dts: msm: Add regulator switch for Dual LED flash in SM6150

Add regulator switch to flash both white LED
and warm white LED simultaneously in SM6150.

CRs-Fixed: 2312917
Change-Id: Id57279098d352d11921c368b3113bb6b61bf2a7d
Signed-off-by: Om Parkash <oparkash@codeaurora.org>