m68k/m68knommu: Implement __get_user_unaligned/__put_user_unaligned()

fs/btrfs/ioctl.c: In function ‘btrfs_ioctl_file_extent_same’:
fs/btrfs/ioctl.c:2802: error: implicit declaration of function ‘__put_user_unaligned’
Signed-off-by: NGeert Uytterhoeven <geert@linux-m68k.org>

arch/m68k/include/asm/uaccess.h

@@ -3,3 +3,10 @@
 #else
 #include <asm/uaccess_mm.h>
 #endif
+
+#ifdef CONFIG_CPU_HAS_NO_UNALIGNED
+#include <asm-generic/uaccess-unaligned.h>
+#else
+#define __get_user_unaligned(x, ptr)	__get_user((x), (ptr))
+#define __put_user_unaligned(x, ptr)	__put_user((x), (ptr))
+#endif