Remove android_atomic_swap from mips & mips64.

Looks like this got left behind in mips by mistake, and
84c3e9923108122045d689f1d2412359ad5208eb carried this over to mips64.
Clean up before it wastes any more time...

Change-Id: I6aeaa6e68be81f94065589337e2f7d3483e6e43c
2 files changed