ARM: sunxi: add support for H2+ SoC

Allwinner H2+ is a quad-core Cortex-A7 SoC.

It is very like H3, that they share the same SoC ID (0x1680), and H3
memory maps as well as drivers works well on the SoC.
Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>

Documentation/arm/sunxi/README

@@ -63,6 +63,10 @@ SunXi family
         + User Manual
           http://dl.linux-sunxi.org/A33/A33%20user%20manual%20release%201.1.pdf
 
+      - Allwinner H2+ (sun8i)
+        + No document available now, but is known to be working properly with
+          H3 drivers and memory map.
+
       - Allwinner H3 (sun8i)
         + Datasheet
           http://dl.linux-sunxi.org/H3/Allwinner_H3_Datasheet_V1.0.pdf

Documentation/devicetree/bindings/arm/sunxi.txt

@@ -12,6 +12,7 @@ using one of the following compatible strings:
   allwinner,sun8i-a23
   allwinner,sun8i-a33
   allwinner,sun8i-a83t
+  allwinner,sun8i-h2-plus
   allwinner,sun8i-h3
   allwinner,sun9i-a80
   allwinner,sun50i-a64

arch/arm/mach-sunxi/sunxi.c

@@ -63,6 +63,7 @@ static const char * const sun8i_board_dt_compat[] = {
 	"allwinner,sun8i-a23",
 	"allwinner,sun8i-a33",
 	"allwinner,sun8i-a83t",
+	"allwinner,sun8i-h2-plus",
 	"allwinner,sun8i-h3",
 	NULL,
 };