rockchip: rk356x-u-boot: Add bootph-all to i2c0_xfer pinctrl node

A RK8XX PMIC is typically using i2c0 on RK356x devices. Add bootph-all
to required pinctrl nodes to simplify use of the prevent booting on
power plug-in option in SPL.

With the following Kconfig options and nodes in u-boot.dtsi the prevent
booting on power plug-in option can work in SPL.

  CONFIG_ROCKCHIP_RK8XX_DISABLE_BOOT_ON_POWERON=y
  CONFIG_SPL_I2C=y
  CONFIG_SPL_POWER=y
  CONFIG_SPL_PINCTRL=y
  CONFIG_SPL_PMIC_RK8XX=y

  &i2c0 {
  	bootph-pre-ram;
  };

  &rk817 {
  	bootph-pre-ram;

  	regulators {
  		bootph-pre-ram;
  	};
  };

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