Remove duplicate definitions of MIN and MAX.

These were needed when bionic's header files were missing these macros (though
it would have made a lot more sense to just fix the header files!) but cause
warnings now.

Change-Id: I65a677122f4f6bd07dffc3f37a0c4c0e823d1bb0
Merge "Remove duplicate definitions of MIN and MAX."
Merge branch 'master' of https://android.googlesource.com/platform/bionic into HEAD