Add explicit casts to uncache.c

Kurian S. reported the following errors:

>bin/uncache.c: In function 'do_data':
>bin/uncache.c:213:6: error: format '%ld' expects argument of type 'long int', but argument 3 has type 'int64_t' [-Werror=format]
>bin/uncache.c: In function 'do_max_alloc':
>bin/uncache.c:308:3: error: format '%lu' expects argument of type 'long unsigned int', but argument 3 has type 'uint64_t' [-Werror=format]
>cc1: all warnings being treated as errors
>make: *** [uncache.o] Error 1

This patch adds explicit casts to supress the warnings.