ARM: dts: stm32: Fix reset for usart1 in scmi configuration

In SCMI configuration, usart1 is secure, so all its resources are secured
(clock and reset) and can't be set/unset by non-secure world but by OP-TEE.

Fixes: 6cccc8d3 ("ARM: dts: stm32: add SCMI version of STM32 boards (DK1/DK2/ED1/EV1)")

Signed-off-by: Patrice Chotard <patrice.chotard@foss.st.com>
Reviewed-by: Patrick Delaunay <patrick.delaunay@foss.st.com>