Implement BOARD_CAMERA_NO_UNWANTED_MSG

On msm7x27 devices, most camera hals appear to spam this message:

lockIfMessageWanted(16): dropped unwanted message

This happens for all camera modes except barcode scanning. If there
is a better fix for this issue, please let me know.

Conflicts:
	services/camera/libcameraservice/Android.mk

(cherry picked from commit 4a441201d19178082f7fc4978dc308c8ac9edf84)

Change-Id: Ie027dc73537f264e16605209646e7b62bc6e6941