[AArch64] Workaround builtin byteswap bug.

The builtin byteswap routines cause critical failure on AArch64 when built with the Android toolchain.
I didn't experience this issue when building for Linux using a local qemu chroot.
Seems to be only an issue with the Android toolchain when building AArch64.
Use our generic version instead.
Merge pull request #1614 from Sonicadvance1/fix_aarch64_bswap

[AArch64] Workaround builtin byteswap bug.