MIPS: Loongson: Oprofile: add a new do_perfcnt_IRQ()

On FuLoong-2F IP6 is shared by the performance counter overflow interrupt
and the Bonito northbridge interrupt.  To reduce overhead only call
do_IRQ() when oprofile is enabled to reduce overhead.

This patch adds an inline function do_perfcnt_IRQ() to hide the #if's ,
which can be shared by the other Loongson machines, i.e. gdium.

Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/1492/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/loongson/lemote-2f/irq.c b/arch/mips/loongson/lemote-2f/irq.c
index c6db7e7..71347d7 100644
--- a/arch/mips/loongson/lemote-2f/irq.c
+++ b/arch/mips/loongson/lemote-2f/irq.c
@@ -79,9 +79,7 @@
 	if (pending & CAUSEF_IP7)
 		do_IRQ(LOONGSON_TIMER_IRQ);
 	else if (pending & CAUSEF_IP6) {	/* North Bridge, Perf counter */
-#if defined(CONFIG_OPROFILE) || defined(CONFIG_OPROFILE_MODULE)
-		do_IRQ(LOONGSON2_PERFCNT_IRQ);
-#endif
+		do_perfcnt_IRQ();
 		bonito_irqdispatch();
 	} else if (pending & CAUSEF_IP3)	/* CPU UART */
 		do_IRQ(LOONGSON_UART_IRQ);