serial: sh-sci: Provide a helper for muxed IRQs.

All of the muxed IRQs presently populate the IRQ array verbosely, this
simply provides a trivial helper to do it for them.

Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/linux/serial_sci.h b/include/linux/serial_sci.h
index 789acf5..01ffe7c 100644
--- a/include/linux/serial_sci.h
+++ b/include/linux/serial_sci.h
@@ -34,6 +34,14 @@
 	SCIx_NR_IRQS,
 };
 
+#define SCIx_IRQ_MUXED(irq)		\
+{					\
+	[SCIx_ERI_IRQ]	= (irq),	\
+	[SCIx_RXI_IRQ]	= (irq),	\
+	[SCIx_TXI_IRQ]	= (irq),	\
+	[SCIx_BRI_IRQ]	= (irq),	\
+}
+
 struct device;
 
 /*