spi: stm32: fix missing device mode capability in stm32mp25

The STM32MP25 SOC has capability to behave in device mode however
missing .has_device_mode within its stm32mp25_spi_cfg structure leads
to not being able to enable the device mode.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Link: https://patch.msgid.link/20241009-spi-mp25-device-fix-v1-1-8e5ca7db7838@foss.st.com


Signed-off-by: Mark Brown <broonie@kernel.org>