dts: arm: st: Add STM32L433 dtsi file

The STM32L433 has the same layout than the STM32L432, additionally it
has GPIOD, GPIOE, I2C2, USART3 and SPI2.

Also move USART3 and SPI2 out of stm32l4.dtsi since STM32L432 does not
have it.

Fixes #10909.

Signed-off-by: Markus Roppelt <markus.roppelt@gmx.de>