ARM: sunxi: Support the Nextthing GR8

The GR8 is an SoC made by Nextthing Co, loosely based on the sun5i family.

It has a number of new controllers compared to the A10s and A13 (SPDIF, I2S),
but some controllers missing too (Ethernet, less I2C, less UARTs).

Signed-off-by: Maxime Ripard <[e-mail]>
Acked-by: Chen-Yu Tsai <[e-mail]>
Signed-off-by: Maxime Ripard <[e-mail]>

Documentation/arm/sunxi/README

···
         + User Manual
           http://dl.linux-sunxi.org/A13/A13%20User%20Manual%20-%20v1.2%20%282013-01-08%29.pdf
 
+      - Next Thing Co GR8 (sun5i)
+
     * Dual ARM Cortex-A7 based SoCs
       - Allwinner A20 (sun7i)
         + User Manual

Documentation/devicetree/bindings/arm/sunxi.txt

···
   allwinner,sun8i-a83t
   allwinner,sun8i-h3
   allwinner,sun9i-a80
+  nextthing,gr8

MAINTAINERS

···
 L:	[e-mail] (moderated for non-subscribers)
 S:	Maintained
 N:	sun[x456789]i
+F:	arch/arm/boot/dts/ntc-gr8*
 
 ARM/Allwinner SoC Clock Support
 M:	Emilio López <[e-mail]>

arch/arm/mach-sunxi/sunxi.c

···
 	"allwinner,sun5i-a10s",
 	"allwinner,sun5i-a13",
 	"allwinner,sun5i-r8",
+	"nextthing,gr8",
 	NULL,
 };