[PATCH] [Embtk] [compiler-rt] ASAN: Add mips support

This simple patch makes asan compile for mips (tested on mips32r2el).
The following test code:
int main()
  char *x = (char*)malloc(10 * sizeof(char*));
  return x[5];

leads to the following output at runtime:

It would help to enable compiler-rt tests on mips builders to ensure
we don't regress.


Nice patch, thanks!
Enabling the tests on mips builders is a good idea too; it could go separately.