build: Clean up QCOM flag definitions

Change-Id: I66bca2db83260ccd65b82e540ee9f7961f00b030
build: Add QCOM flags to Clang CFLAGS

Change-Id: I56f0d4106f5d3d27c1ace744d30c1c81f0052bbd
build: Remove unused qcom CFLAG

Change-Id: I6ead3e57899bcb007d4d284901f918a65a9e6926