bpftool: Fix typo in error message

s/at at/at a/

Signed-off-by: Thorsten Blum <[e-mail]>
Signed-off-by: Daniel Borkmann <[e-mail]>
Acked-by: Quentin Monnet <[e-mail]>
Link: https://lore.kernel.org/bpf/[e-mail]

tools/bpf/bpftool/prog.c

···
 		NEXT_ARG();
 	}
 	if (selected_cnt > MAX_NUM_PROFILE_METRICS) {
-		p_err("too many (%d) metrics, please specify no more than %d metrics at at time",
+		p_err("too many (%d) metrics, please specify no more than %d metrics at a time",
 		      selected_cnt, MAX_NUM_PROFILE_METRICS);
 		return -1;
 	}