m68k: Enable atomic64_t

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/Kconfig

@@ -7,6 +7,7 @@ config M68K
 	default y
 	select HAVE_AOUT
 	select HAVE_IDE
+	select GENERIC_ATOMIC64
 
 config MMU
 	bool

arch/m68k/include/asm/atomic.h

@@ -3,3 +3,5 @@
 #else
 #include "atomic_mm.h"
 #endif
+
+#include <asm-generic/atomic64.h>