lib: div64: add missing include

Include the function its prototype to prevent the warning
that it has no prototype.

Signed-off-by: Jeroen Hofstee <jeroen@myspectrum.nl>

lib/div64.c

@@ -16,6 +16,7 @@
  * assembly versions such as arch/powerpc/lib/div64.S and arch/sh/lib/div64.S.
  */
 
+#include <div64.h>
 #include <linux/types.h>
 
 uint32_t __div64_32(uint64_t *n, uint32_t base)