[PATCH 0/4] meson_uart: add support for core clock handling

[Helmut Klein]

to be able to use the none AO uarts of the s905 SoCs, the core clock has 
to be enabled.
(see chapter 22.3 of the public s905 data sheet)
at least the u-boot of my s905 based media player (netxeon minimx) 
doesn't do this.
so the driver has to do this.

this patch set does:
- exposes the CLKID_UART0 to the dtb
- adds documentation for the dt-bindings of meson_uart
- adds the core clock handling to the driver

none of the available s905 dts use uart_A actively. so there is no patch 
for any of the existing dts files.