mips: fix bug.h build regression

Commit 37778088 ("bug.h: need linux/kernel.h for TAINT_WARN.") broke
all MIPS builds:

    CC      arch/mips/kernel/machine_kexec.o
  include/linux/log2.h: In function '__ilog2_u32':
  include/linux/log2.h:34:2: error: implicit declaration of function 'fls' [-Werror=implicit-function-declaration]
  include/linux/log2.h: In function '__ilog2_u64':
  include/linux/log2.h:42:2: error: implicit declaration of function 'fls64' [-Werror=implicit-function-declaration]
  ...
Signed-off-by: Yoichi Yuasa <yuasa@linux-mips.org>
Tested-by: John Crispin <blogic@openwrt.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/mips/include/asm/bitops.h

@@ -17,7 +17,6 @@
 #include <linux/irqflags.h>
 #include <linux/types.h>
 #include <asm/barrier.h>
-#include <asm/bug.h>
 #include <asm/byteorder.h>		/* sigh ... */
 #include <asm/cpu-features.h>
 #include <asm/sgidefs.h>

arch/mips/include/asm/io.h

@@ -17,6 +17,7 @@
 #include <linux/types.h>
 
 #include <asm/addrspace.h>
+#include <asm/bug.h>
 #include <asm/byteorder.h>
 #include <asm/cpu.h>
 #include <asm/cpu-features.h>