ARM: configs: Add STM32 defconfig

This patch adds a new config for STM32 MCUs.
STM32F429 Discovery board boots successfully with this config applied.

Tested-by: Chanwoo Choi <cw00.choi@samsung.com>
Signed-off-by: Maxime Coquelin <mcoquelin.stm32@gmail.com>
1 file changed