mips: Use the generic bitops headers

The generic bitops headers are required when calling logarithmic
functions, such as ilog2().

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Reviewed-by: Daniel Schwierzeck <daniel.schwierzeck@gmail.com>

arch/mips/include/asm/bitops.h

@@ -17,6 +17,11 @@
 #include <asm/sgidefs.h>
 #include <asm/system.h>
 
+#include <asm-generic/bitops/fls.h>
+#include <asm-generic/bitops/__fls.h>
+#include <asm-generic/bitops/fls64.h>
+#include <asm-generic/bitops/__ffs.h>
+
 /*
  * clear_bit() doesn't provide any barrier for the compiler.
  */