MIPS: Lemote 2F: Fix build caused by recent mass rename.

  CC      arch/mips/loongson64/lemote-2f/clock.o
/home/ralf/src/linux/linux-mips/arch/mips/loongson64/lemote-2f/clock.c:18:40: fatal error: asm/mach-loongson/loongson.h: No such file or directory
 #include <asm/mach-loongson/loongson.h>
                                        ^
compilation terminated.

Signed-off-by: Ralf Baechle <ralf@linux-mips.org>