Without the prefix, "same-as-spl" in `u-boot,spl-boot-order` will not work
as expected. When board_boot_order() `spl-boot-order.c` meets
"same-as-spl", it gets the conf by looking the boot_devices table by boot
source, and parse the node by the conf with:

   node = fdt_path_offset(blob, conf);

which will failed without the "/" indicating the path.

Currently only entries of boot_devices in rk3399 have the "/" prefix.
Therefore add the missing ones in other boards.
Signed-off-by: NLevin Du <djw@t-chip.com.cn>
Reviewed-by: NPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>
Reviewed-by: NKever Yang <kever.yang@rock-chips.com>

The setting for noc remap should goto arch_cpu_init().
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>

The driver need a mapping to get the dts node by boot srouce ID.
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>

Clean up the rk3188.c so that we can re-use the common spl board file.
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>

The SoC feature init will be better to use arch_cpu_init() and
goes to soc file.
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>

Use board_debug_uart_init() for UART iomux init instead of
do it in board_init_f, and move the function to soc file so
that we can find all the soc/board setting in soc file and
use a common board file.
Signed-off-by: NKever Yang <kever.yang@rock-chips.com>
Reviewed-by: NPhilipp Tomsich <philipp.tomsich@theobroma-systems.com>