sunxi: Add support for the rsb (Reduced Serial Bus)

sun8i (A23) introduces a new bus for communicating with the pmic, the rsb,
the rsb is also used to communicate with the pmic on the A80, and is
documented in the A80 user manual.

This commit adds support for this based on the rsb driver from the allwinner
u-boot sources.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>
diff --git a/arch/arm/include/asm/arch-sunxi/cpu.h b/arch/arm/include/asm/arch-sunxi/cpu.h
index adf203a..bcfa00d 100644
--- a/arch/arm/include/asm/arch-sunxi/cpu.h
+++ b/arch/arm/include/asm/arch-sunxi/cpu.h
@@ -129,6 +129,7 @@
 #define SUNXI_R_UART_BASE		0x01f02800
 #define SUNXI_R_PIO_BASE		0x01f02c00
 #define SUN6I_P2WI_BASE			0x01f03400
+#define SUNXI_RSB_BASE			0x01f03400
 
 /* CoreSight Debug Module */
 #define SUNXI_CSDM_BASE			0x3f500000