xea: spl: Disable pull UP for GPIO0_2{35}

On the imx287 pin GPMI_WRN (GPIO0_25) no PullUP is available that can be
enabled.

To get the same behavior for both boot select pins (i.e. GPIO0_2{35})
disable pull UPs on both.

Signed-off-by: Lukasz Majewski <lukma@denx.de>