ARM: shmobile: r8a7791: Add IRQC clock to device tree

Link the external IRQ controller irqc0 to the IRQC module clock, so it
can be power managed using that clock.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
diff --git a/include/dt-bindings/clock/r8a7791-clock.h b/include/dt-bindings/clock/r8a7791-clock.h
index 8fc5dc8..4022683 100644
--- a/include/dt-bindings/clock/r8a7791-clock.h
+++ b/include/dt-bindings/clock/r8a7791-clock.h
@@ -70,6 +70,9 @@
 #define R8A7791_CLK_USBDMAC0		30
 #define R8A7791_CLK_USBDMAC1		31
 
+/* MSTP4 */
+#define R8A7791_CLK_IRQC		7
+
 /* MSTP5 */
 #define R8A7791_CLK_AUDIO_DMAC1		1
 #define R8A7791_CLK_AUDIO_DMAC0		2