rockchip: rk3399-pinebook-pro: Sync DT from v6.8 and update defconfig

rockchip: rk3399-pinebook-pro: Sync DT from v6.8 and update defconfig

Sync rk3399-pinebook-pro device tree from Linux kernel v6.8.

Add SF_DEFAULT_SPEED=10000000 and SPI_FLASH_SFDP_SUPPORT=y to improve
support for booting from SPI flash.

Add CMD_POWEROFF=y to support poweroff using cmdline and power on using
the pwr button on the board.

Remove SPL_TINY_MEMSET=y to use full memset in SPL.

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