dt-bindings: arm: stm32: Add compatible strings for Protonic boards

dt-bindings: arm: stm32: Add compatible strings for Protonic boards

Add compatible strings for Protonic MECIO1r0 and MECT1S boards to the
STM32MP151-based boards section and Protonic MECIO1r1 board to the
STM32MP153-based boards section.

MECIO1 is an I/O and motor control board used in blood sample analysis
machines. MECT1S is a 1000Base-T1 switch for internal machine networks
of blood sample analysis machines.

Signed-off-by: Oleksij Rempel <o.rempel@pengutronix.de>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>