arm: stm32f4: Do not enable USART1/USART2 by default

Not all the boards (for instance the Nuclo F412) use USART1 or USART2.
Let each board enable these USARTs when really used.

Change-Id: Idfe79c724bd7b1ab154310b4a8234b52eef2298d
Signed-off-by: Florian Vaussard <florian.vaussard@heig-vd.ch>
diff --git a/arch/arm/soc/st_stm32/stm32f4/Kconfig.defconfig.series b/arch/arm/soc/st_stm32/stm32f4/Kconfig.defconfig.series
index cc581d5..e1fa08e 100644
--- a/arch/arm/soc/st_stm32/stm32f4/Kconfig.defconfig.series
+++ b/arch/arm/soc/st_stm32/stm32f4/Kconfig.defconfig.series
@@ -26,18 +26,6 @@
 config UART_STM32
 	def_bool y
 
-config UART_STM32_PORT_1
-	def_bool y
-
-config UART_STM32_PORT_1_NAME
-	default UART_1
-
-config UART_STM32_PORT_2
-	def_bool y
-
-config UART_STM32_PORT_2_NAME
-	default UART_2
-
 endif #SERIAL
 
 if CLOCK_CONTROL