configs/stm32mp157_dk_defconfig: switch to mainline 5.3.7 linux version

Switch to the official Linux repository since
the board has been officially supported.

Signed-off-by: Bartosz Bilas <b.bilas@grinn-global.com>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>

configs/stm32mp157_dk_defconfig

@@ -1,12 +1,12 @@
 BR2_arm=y
 BR2_cortex_a7=y
-BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_4_19=y
+BR2_PACKAGE_HOST_LINUX_HEADERS_CUSTOM_5_3=y
 BR2_ROOTFS_OVERLAY="board/stmicroelectronics/stm32mp157-dk/overlay/"
 BR2_ROOTFS_POST_IMAGE_SCRIPT="support/scripts/genimage.sh"
 BR2_ROOTFS_POST_SCRIPT_ARGS="-c board/stmicroelectronics/stm32mp157-dk/genimage.cfg"
 BR2_LINUX_KERNEL=y
-BR2_LINUX_KERNEL_CUSTOM_TARBALL=y
-BR2_LINUX_KERNEL_CUSTOM_TARBALL_LOCATION="$(call github,STMicroelectronics,linux,v4.19-stm32mp-r1.5)/linux-v4.19-stm32mp-r1.5.tar.gz"
+BR2_LINUX_KERNEL_CUSTOM_VERSION=y
+BR2_LINUX_KERNEL_CUSTOM_VERSION_VALUE="5.3.7"
 BR2_LINUX_KERNEL_USE_CUSTOM_CONFIG=y
 BR2_LINUX_KERNEL_CUSTOM_CONFIG_FILE="board/stmicroelectronics/stm32mp157-dk/linux.config"
 BR2_LINUX_KERNEL_DTS_SUPPORT=y