Use machine/atomic.h instead of gcc built-in atomics for FreeBSD/mips.

Gcc built-in atomics are not supported for FreeBSD/mips.
Use machine/atomic.h instead of gcc built-in atomics for FreeBSD/mips.

Gcc built-in atomics are not supported for FreeBSD/mips.
Use machine/atomic.h instead of gcc built-in atomics for FreeBSD/mips.

Gcc built-in atomics are not supported for FreeBSD/mips.