soc: arm: st_stm32: use SMPS power supply only if enabled

Use SMPS power supply only if enabled.

The default power supply configuration for the
NUCLEO board with -Q subfix is SMPS,
so it's essential to match with hardware configuration
to avoid deadlocks due to mismatch.

if a custom board with LDO configuration is in use,
then no need to enable `CONFIG_POWER_SUPPLY_SMPS`
Signed-off-by: Manojkumar Subramaniam <manoj@electrolance.com>

soc/arm/st_stm32/stm32h7/soc_m7.c

@@ -80,8 +80,10 @@ static int stm32h7_init(const struct device *arg)
 	SystemCoreClock = 64000000;
 
 	/* Power Configuration */
-#ifdef SMPS
+#if defined(SMPS) && defined(CONFIG_POWER_SUPPLY_SMPS)
 	LL_PWR_ConfigSupply(LL_PWR_DIRECT_SMPS_SUPPLY);
+#elif defined(CONFIG_POWER_SUPPLY_SMPS)
+#error Unsupported configuration: Selected SoC do not support SMPS
 #else
 	LL_PWR_ConfigSupply(LL_PWR_LDO_SUPPLY);
 #endif