short_types: Fix warning in test

Our project builds the ccan tests with -Wextra, so we get warnings about
the unused variables.
Signed-off-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

ccan/short_types/test/run-endian.c

@@ -4,7 +4,7 @@
 #include <stdlib.h>
 #include <err.h>
 
-int main(int argc, char *argv[])
+int main(void)
 {
 	plan_tests(6);
 

ccan/short_types/test/run.c

@@ -3,7 +3,7 @@
 #include <stdlib.h>
 #include <err.h>
 
-int main(int argc, char *argv[])
+int main(void)
 {
 	plan_tests(16);