Recent gcc versions generate more warnings when compiling util/zbin.c
on a 64-bit system:

util/zbin.c: In function `read_file':
util/zbin.c:85: warning: format `%d' expects type `int', but
                argument 3 has type `size_t'
util/zbin.c:91: warning: format `%d' expects type `int', but
                argument 3 has type `size_t'
util/zbin.c: In function `read_zinfo_file':
util/zbin.c:119: warning: format `%d' expects type `int', but
                 argument 4 has type `size_t'
util/zbin.c: In function `alloc_output_file':
util/zbin.c:134: warning: format `%d' expects type `int', but
                 argument 3 has type `size_t'
util/zbin.c: In function `process_zinfo_add':
util/zbin.c:244: warning: format `%d' expects type `int', but
                 argument 3 has type `size_t'
util/zbin.c:266: warning: format `%d' expects type `int', but
                 argument 7 has type `size_t'
util/zbin.c:286: warning: format `%#x' expects type `unsigned int',
                 but argument 7 has type `size_t'
util/zbin.c: In function `write_output_file':
util/zbin.c:348: warning: format `%d' expects type `int', but
                 argument 3 has type `size_t'

This patch eliminates these warnings.

Signed-off-by: Marty Connor <mdc@etherboot.org>