tools: bpftool: remove new lines from errors

It's a little bit unusual for kernel style, but we add the new line
character to error strings inside the p_err() function.  We do this
because new lines at the end of error strings will break JSON output.

Fix a few p_err("..\n") which snuck in recently.

Fixes: 5ccda64d38cc ("bpftool: implement cgroup bpf operations")
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
diff --git a/tools/bpf/bpftool/prog.c b/tools/bpf/bpftool/prog.c
index 5577960..c6a28be 100644
--- a/tools/bpf/bpftool/prog.c
+++ b/tools/bpf/bpftool/prog.c
@@ -813,12 +813,12 @@ static int do_load(int argc, char **argv)
 		usage();
 
 	if (bpf_prog_load(argv[0], BPF_PROG_TYPE_UNSPEC, &obj, &prog_fd)) {
-		p_err("failed to load program\n");
+		p_err("failed to load program");
 		return -1;
 	}
 
 	if (do_pin_fd(prog_fd, argv[1])) {
-		p_err("failed to pin program\n");
+		p_err("failed to pin program");
 		return -1;
 	}