tools/bpftool: Fix skeleton codegen

Remove unnecessary check at the end of codegen() routine which makes codegen()
to always fail and exit bpftool with error code. Positive value of variable
n is not an indicator of a failure.

Fixes: 2c4779e ("tools, bpftool: Exit on error in function codegen")
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Reviewed-by: Tobias Klauser <tklauser@distanz.ch>
Link: https://lore.kernel.org/bpf/20200612201603.680852-1-andriin@fb.com

Author: anakryiko

tools/bpf/bpftool/gen.c

@@ -257,8 +257,6 @@ static void codegen(const char *template, ...)
 	va_end(args);
 
 	free(s);
-	if (n)
-		exit(-1);
 }
 
 static int do_skeleton(int argc, char **argv)