ARM: dts: stm32mp: Repair damage from alignment with v6.3

The patch fixed by this commit renders ST STM32MP15xx EV1 board and
all DHSOM SoM based boards unbootable from SPI NOR. Fix the damage
by updating -u-boot.dtsi to match the stm32mp15-pinctrl.dtsi update.

Fixes: 08002ffd ("ARM: dts: stm32mp: alignment with v6.3")
Signed-off-by: Marek Vasut <marex@denx.de>
Reviewed-by: Patrice Chotard <patrice.chotard@foss.st.com>