BoardConfigQcom: Fix setting UM4.9 and UM4.14 specific flags

Calling is-board-platform-in-list from this makefile was not
returning the desirable output, thus resulting in a failure
to meet the conditions for the UM4.9 and UM4.14 family platforms.

Due to the fact that this makefile is included in a very early
stage in the build process, the QCOM macros are not defined.
Simply use standard macros like in rest of the makefile.

Change-Id: Iad889882f94167f1bc1761ddd549dac9dcdee3ba