rockchip: rk3568-nanopi-r5: Update defconfig for NanoPi R5C and R5S

Update and sync Kconfig options for NanoPi R5C and NanoPi R5S with other
RK3568 boards.

SPL_FIT_SIGNATURE is enabled to add a checksum validation of the FIT
payload, also add LEGACY_IMAGE_FORMAT to keep boot scripts working.

OF_SPL_REMOVE_PROPS, SPL_DM_SEQ_ALIAS and SPL_PINCTRL change ensure
pinctrl for eMMC, SD-card and UART2 is applied in SPL.

MMC_HS200_SUPPORT and SPL counterpart is enabled to speed up eMMC load
times from on-board eMMC 5.1 modules.

Drop remaining unused or unsupported options to sync with other RK3568
boards.

Also sync device tree from linux v6.4 and drop u-boot,spl-boot-order and
use the default from rk356x-u-boot.dtsi.

Signed-off-by: Jonas Karlman <jonas@kwiboo.se>
Reviewed-by: Kever Yang <kever.yang@rock-chips.com>