stm32mp: Cleanup DEBUG UART configuration

For early debug uart is assumed already initialized by OP-TEE and
CONFIG_DEBUG_UART_BOARD_INIT and DEBUG_UART_CLOCK are not used
in stm32 serial driver except in SPL for STM32MP15 family.

This patch cleanups the Kconfig for other SoC, so activate
CONFIG_DEBUG_UART is enough to activate the U-Boot early trace.

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Change-Id: Ia45214cd1de6af9cc9e01119b85668621b6b8dce
Reviewed-on: https://gerrit.st.com/c/mpu/oe/st/u-boot/+/433035
Reviewed-by: Patrice CHOTARD <patrice.chotard@foss.st.com>
ACI: CIBUILD <MDG-smet-aci-builds@list.st.com>
Domain-Review: Patrice CHOTARD <patrice.chotard@foss.st.com>

Author: patrickdelaunay

arch/arm/mach-stm32mp/Kconfig.21x

@@ -29,13 +29,12 @@ config BOOTSTAGE_STASH_ADDR
 
 if DEBUG_UART
 
-config DEBUG_UART_BOARD_INIT
-	default y
-
 # debug on USART2 by default
 config DEBUG_UART_BASE
 	default 0x400e0000
 
+config DEBUG_UART_CLOCK
+	default 0
 endif
 
 source "board/st/stm32mp2/Kconfig"

arch/arm/mach-stm32mp/Kconfig.23x

@@ -29,13 +29,12 @@ config BOOTSTAGE_STASH_ADDR
 
 if DEBUG_UART
 
-config DEBUG_UART_BOARD_INIT
-	default y
-
 # debug on USART2 by default
 config DEBUG_UART_BASE
 	default 0x400e0000
 
+config DEBUG_UART_CLOCK
+	default 0
 endif
 
 source "board/st/stm32mp2/Kconfig"

arch/arm/mach-stm32mp/Kconfig.25x

@@ -29,13 +29,12 @@ config BOOTSTAGE_STASH_ADDR
 
 if DEBUG_UART
 
-config DEBUG_UART_BOARD_INIT
-	default y
-
 # debug on USART2 by default
 config DEBUG_UART_BASE
 	default 0x400e0000
 
+config DEBUG_UART_CLOCK
+	default 0
 endif
 
 source "board/st/stm32mp2/Kconfig"