feat(stm32mp2-fdts): add I2C7 pin muxing

It will be used for PMIC on STM32MP257F-EV board.

Signed-off-by: Yann Gautier <yann.gautier@foss.st.com>
Change-Id: I7f95220512de4416323b381fec7c7dcb044c64fd
1 file changed