pinctrl: sun6i: Add some missing functions, fix i2c3 muxing

While working on pinctrl for the A31s, I noticed that function 4 of
PA15 - PA18 was missing, add these.

I also noticed that i2c3 sck / sda got assigned to PB5 & PB6, this should
be PB4 & PB5, fix this as well.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
pinctrl: sun6i: Add A31s pinctrl support

The A31s is a stripped down version of the A31, as such it is missing some
pins and some functions on some pins.

The new pinctrl-sun6i-a31s.c this commit adds is a copy of pinctrl-sun6i-a31s.c
with the missing pins and functions removed.

Note there is no a31s specific version of pinctrl-sun6i-a31-r.c, as the
prcm pins are identical between the A31 and the A31s.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: sunxi: Add "allwinner,sun6i-a31s" to mach-sunxi

So fat the A31s is 100% compatible with the A31, still lets do the same
as what we've done for the A13 / A10s and give it its own compatible string,
in case need to differentiate later.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun6i: Add sun6i-a31s.dtsi

Add a dtsi file for A31s based boards. This is a copy of sun6i-a31.dtsi, with:

-The main pinctrl compatible changed to allwinner,sun6i-a31s.dtsi
-The ohci2 controller is present according to the data-sheet, but not routed
 to the outside, so remove it from the dtsi as having an always disabled node
 is not useful.

All the other nodes present in the original sun6i-a31.dtsi are present in
the A31s too, and are 100% compatible.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
ARM: dts: sun6i: Add dts file for CSQ CS908 board

The CSQ CS908 is an A31s based top-set box, with 1G RAM, 8G NAND,
rtl8188etv usb wifi, 2 USB A receptacles (1 connected through the OTG
controller), ethernet, 3.5 mm jack with a/v out and hdmi out:

http://www.geekbuying.com/item/CS908-Allwinner-A31S-Quad-Core-1-2GHz-Android-4-4-Mini-TV-Box-HDMI-HDD-Player-1G-8G-WIFI-Miracast---Black-333395.html

Note it has no sdcard slot and therefore can only be fel booted.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>