LoongArch/irq: Use seq_put_decimal_ull_width() for decimal values

Performance improvement for reading /proc/interrupts on LoongArch.

On a system with n CPUs and m interrupts, there will be n*m decimal
values yielded via seq_printf(.."%10u "..) which is less efficient than
seq_put_decimal_ull_width(), stress reading /proc/interrupts indicates
~30% performance improvement with this patch (and its friends).

Signed-off-by: David Wang <00107082@163.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

Author: zq-david-wang

arch/loongarch/kernel/smp.c

@@ -82,7 +82,7 @@ void show_ipi_list(struct seq_file *p, int prec)
 	for (i = 0; i < NR_IPI; i++) {
 		seq_printf(p, "%*s%u:%s", prec - 1, "IPI", i, prec >= 4 ? " " : "");
 		for_each_online_cpu(cpu)
-			seq_printf(p, "%10u ", per_cpu(irq_stat, cpu).ipi_irqs[i]);
+			seq_put_decimal_ull_width(p, " ", per_cpu(irq_stat, cpu).ipi_irqs[i], 10);
 		seq_printf(p, " LoongArch  %d  %s\n", i + 1, ipi_types[i]);
 	}
 }