plat-stm32mp2: fix test on CFG_STM32_UART

Fix test directive on CFG_STM32_UART that boolean CFG_ configuration
switches do not have a meaningful value.

Fixes: bd1fffe ("plat-stm32mp2: add new platform support")
Reviewed-by: Jerome Forissier <[email protected]>
Reviewed-by: Jens Wiklander <[email protected]>
Signed-off-by: Etienne Carriere <[email protected]>

core/arch/arm/plat-stm32mp2/main.c

@@ -60,7 +60,7 @@ static struct stm32_uart_pdata console_data;
 
 void console_init(void)
 {
-#if CFG_STM32_UART
+#ifdef CFG_STM32_UART
 	/* Early console initialization before MMU setup */
 	struct uart {
 		paddr_t pa;