Build - [HAX] Allow per-target dtbTool

* Revert this when fixed

build: Default to dtbToolCM

* The default dtbTool isn't the correct module name for the module that
actually lives in device/qcom/common/dtbtool

Change-Id: I25ba71fda66c9943e0500ce818cb70db07750abe
Signed-off-by: STELIX <ssspinni@gmail.com>