ARM: dts: msm: enable camera on SDM450 with Nebula

Enabling both front and rear camera sensors.
Taken msm 8953 dtsi snapshot from msm_4.4 at
commit 6b83a15ee1192 ("xhci: plat: Fix xhci_plat
shutdown hung")

From 8953 dtsi, derived sdm632 dtsi and changed
Digital voltage settings as per hardware
recommendation.

Change-Id: Ibf6202a6a24d415b3d0f3e6ed67b4138c2a0c78e
Signed-off-by: Vijay kumar Tumati <vtumati@codeaurora.org>