scripts: kallsyms: Use %zu to print 'size_t'

Commit f3462aa9 (Kbuild: Handle longer symbols in kallsyms.c) introduced the
following warning on ARM:

scripts/kallsyms.c:121:4: warning: format '%lu' expects argument of type 'long unsigned int', but argument 4 has type 'size_t' [-Wformat]

Use %zu to print 'size_t'.
Signed-off-by: NFabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: NMichal Marek <mmarek@suse.cz>

scripts/kallsyms.c

@@ -112,7 +112,7 @@ static int read_symbol(FILE *in, struct sym_entry *s)
 		return -1;
 	}
 	if (strlen(str) > KSYM_NAME_LEN) {
-		fprintf(stderr, "Symbol %s too long for kallsyms (%lu vs %d).\n"
+		fprintf(stderr, "Symbol %s too long for kallsyms (%zu vs %d).\n"
                                 "Please increase KSYM_NAME_LEN both in kernel and kallsyms.c\n",
 			str, strlen(str), KSYM_NAME_LEN);
 		return -1;