ARM: dts: msm: reduce panel regulator on delay for msm8996

DSI driver waits for 40ms after turning on the LAB/IBB/LDO14
regulator on msm8996 target. This delay is much higher than
required delay. This change optimizes the delay.

Change-Id: I32111bf47e1ab33bd04baa1f5824c3b47e07c658
Signed-off-by: Dhaval Patel <pdhaval@codeaurora.org>