configs/stm32mp157a_dk1: remove uboot config fragment

Running stm32mp1 watchdog is properly recognized and handled by kernel
watchdog framework since Linux v5.6.

Reported-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>
Signed-off-by: Pierre-Jean Texier <texier.pj2@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/stmicroelectronics/stm32mp157a-dk1/uboot-fragment.config

@@ -1 +0,0 @@
-# CONFIG_STM32MP_WATCHDOG is not set

configs/stm32mp157a_dk1_defconfig

@@ -27,7 +27,6 @@ BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2021.07"
 BR2_TARGET_UBOOT_BOARD_DEFCONFIG="stm32mp15_trusted"
-BR2_TARGET_UBOOT_CONFIG_FRAGMENT_FILES="board/stmicroelectronics/stm32mp157a-dk1/uboot-fragment.config"
 # BR2_TARGET_UBOOT_FORMAT_BIN is not set
 BR2_TARGET_UBOOT_FORMAT_STM32=y
 BR2_TARGET_UBOOT_CUSTOM_MAKEOPTS="DEVICE_TREE=stm32mp157a-dk1"