Revert "Enable cross-compilation across architectures on android"

This reverts commit r276333.

As I commented in the review (https://reviews.llvm.org/D22415), this change isn't needed because CMAKE_C_FLAGS is implicitly added by CMake to the command line for all C source files.

With this patch enabled CMAKE_C_FLAGS is duplicated on all C sources, and applied to ASM sources, which is not ideal.

I sent an email about this to llvm-commits on the commit thread. I suspect the problem the patch author was actually seeing is that CMAKE_C_FLAGS isn't applied to ASM files, and the builtins library has quite a few of those. The correct solution there is to specify CMAKE_ASM_FLAGS with whatever flags need to be passed to the compiler when compiling ASM files.

If there are other problems with flag propagation, please let me know.

llvm-svn: 276683