ARM: dts: stm32: don't mix SCMI and non-SCMI board compatibles

The binding erroneously decreed that the SCMI variants of the ST
evaluation kits are compatible with the non-SCMI variants.

This is not correct, as a kernel or bootloader compatible with the non-SCMI
variant is not necessarily able to function, when direct access
to resources is replaced by having to talk SCMI to the secure monitor.

The binding has been adjusted to reflect thus, so synchronize the device
trees now.

Fixes: 5b7e5831 ("ARM: dts: stm32: Add SCMI version of STM32 boards (DK1/DK2/ED1/EV1)")
Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>