[HAX] Allow per-target dtbTool

[HAX] Allow per-target dtbTool

 * Revert this when fixed

Change-Id: I97ecb0448ae7bd5859454be290c5dde6248b2859

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: I80b427e3652b99742573bc4d2829e51645a8822b

generate_extra_images: Look for 3.10 dtbs

The dtbs have changed location between 3.4 and 3.10. Look for the
new location first and fallback to the 3.4 location if they're
missing.

Change-Id: I7aada8dbcf01ea6f62b3235b452c9329cd69e5e8

build: Generalize kernel DTB path

Use $TARGET_KERNEL_ARCH to specify the architecture-dependent
path location of the DTB files.

Change-Id: I302f407d987e1b33acb0e47b284a1cb793747691

generate_extra_images: Allow supplying arguments to dtbtool

* Also add a message to indicate when dt.img is generated

Change-Id: I670cc8aa571269d1dc1085e51b063fb890dc05f2