[libgcc] Change __divmoddi4 from int64 [unknown] to int64_t

Matches the header file libgcc.h and solves

  __divmoddi4.c:3:56: error: unknown type name ‘int64’

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/libgcc/__divmoddi4.c

@@ -1,6 +1,6 @@
 #include "libgcc.h"
 
-__libgcc int64_t __divmoddi4(int64_t num, int64_t den, int64 *rem_p)
+__libgcc int64_t __divmoddi4(int64_t num, int64_t den, int64_t *rem_p)
 {
   int minus = 0;
   int64_t v;