qcacmn: Add qdf_platform source file to qdf/Kbuild

Add qdf_platform source file to qdf/Kbuild and
clean-up WAR introduced in change
I8172f3dbe0716be24a4dda739afb49f94528a4f6

Change-Id: Icb76d53544590b8bcace275ef52870606fb5d826
5 files changed