dt-bindings: i2c: stm32: update optional properties for stm32h7/stm32mp1

Add STM32H7 and STM32MP1 in the list of compatible socs for each
optional property.

Signed-off-by: Bich Hemon <bich.hemon@st.com>
Reviewed-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>