Fix: "$(srctree) is not clean, please run 'make mrproper" error... If
USES_VMWARE_VIRTUALIZATION = true, then AndroidKernel.mk adds to
KERNEL_OBJ/.config before Makefile runs causing error (Makefile: no config yet)

I could just ignore the configs, or put them in a seperate file...
ie. Makefile, below this rule but I know my builds never run make in srctree.