sunxi: refactor serial base addresses to avoid asm/arch/cpu.h

At the moment we have each SoC's memory map defined in its own cpu.h,
which is included in include/configs/sunxi_common.h. This will be a
problem with the introduction of Allwinner RISC-V support.

Remove the inclusion of that header file from the common config header,
instead move the required serial base addresses (for the SPL) into a
separate header file. Then include the original cpu.h file only where
we really need it, which is only under arch/arm now.

This disentangles the architecture specific header files from the
generic code.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/include/configs/sunxi-common.h b/include/configs/sunxi-common.h
index d2d70f0..b8ca77d 100644
--- a/include/configs/sunxi-common.h
+++ b/include/configs/sunxi-common.h
@@ -12,7 +12,6 @@
 #ifndef _SUNXI_COMMON_CONFIG_H
 #define _SUNXI_COMMON_CONFIG_H
 
-#include <asm/arch/cpu.h>
 #include <linux/stringify.h>
 
 /* Serial & console */
@@ -24,6 +23,7 @@
 #define CFG_SYS_NS16550_CLK		24000000
 #endif
 #if !CONFIG_IS_ENABLED(DM_SERIAL)
+#include <asm/arch/serial.h>
 # define CFG_SYS_NS16550_COM1		SUNXI_UART0_BASE
 # define CFG_SYS_NS16550_COM2		SUNXI_UART1_BASE
 # define CFG_SYS_NS16550_COM3		SUNXI_UART2_BASE