mfd: sun6i-prcm: Add support for Allwinner A23 PRCM

The Allwinner A23 SoC has a PRCM unit like the previous A31 SoC.
The differences are the AR100 clock can no longer be modified,
the APB0 clock has different divisors, and some clock gates are
gone.

This patch adds a compatible with a modified subdevice list for
the A23.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: sunxi: Introduce Allwinner A23 support

The Allwinner A23 is a dual-core Cortex-A7-based SoC. It re-uses most of
the IPs found in previous SoCs, notably the A31.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: sunxi: Add earlyprintk support using R_UART (sun6i/sun8i)

sun6i/sun8i have a UART in the RTC block group, which can be used
as an early console. This is most useful on sun8i as UART0 is muxed
with MMC0, which is not available if we boot from MMC.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: sun8i: Add SMP support for the Allwinner A23

The A23 is a dual Cortex-A7. Add the logic to use the IPs used to
control the CPU configuration and the CPU power so that we can
bring up secondary CPUs at boot.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: sunxi: Add Allwinner A23 dtsi

The Allwinner A23 is a tablet oriented SoC with 2 Cortex-A7 cores
and a Mali-400MP2 GPU.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>
ARM: sun8i: dt: Add Ippo-q8h v5 support

The Ippo-q8h is a tablet circiut board commonly found in cheap Android
tablets with A23 SoCs. There are at least 2 versions of the board, with
different peripherals, such as WiFi chips.

This patch add supports for v5 of such boards, which has a ESP8089 WiFi
chip (not supported) connected to mmc1.

Signed-off-by: Chen-Yu Tsai <wens@csie.org>