build: Separate platform macros from QCOM platform definition

* The macros used in the file formerly called "qcom_utils.mk" are
  actually generic and not QCOM-specific. Move the QCOM_BOARD definitions
  to a QCOM-specific location, and name the remaning macros something more
  generic.

Change-Id: I6747bc9201e56b456caf251122057d7dbc233f1c
6 files changed