smp: Use str_plural() to fix Coccinelle warnings

Fixes the following two Coccinelle/coccicheck warnings reported by
string_choices.cocci:

	opportunity for str_plural(num_cpus)
	opportunity for str_plural(num_nodes)
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20240508154225.309703-2-thorsten.blum@toblux.com

kernel/smp.c

@@ -25,6 +25,7 @@
 #include <linux/nmi.h>
 #include <linux/sched/debug.h>
 #include <linux/jump_label.h>
+#include <linux/string_choices.h>
 
 #include <trace/events/ipi.h>
 #define CREATE_TRACE_POINTS
@@ -982,8 +983,7 @@ void __init smp_init(void)
 	num_nodes = num_online_nodes();
 	num_cpus  = num_online_cpus();
 	pr_info("Brought up %d node%s, %d CPU%s\n",
-		num_nodes, (num_nodes > 1 ? "s" : ""),
-		num_cpus,  (num_cpus  > 1 ? "s" : ""));
+		num_nodes, str_plural(num_nodes), num_cpus, str_plural(num_cpus));
 
 	/* Any cleanup work */
 	smp_cpus_done(setup_max_cpus);