configs/beaglebone_qt5_defconfig: bump to u-boot 2021.04

Fixes:
  /usr/bin/ld: scripts/dtc/dtc-parser.tab.o:(.bss+0x10): multiple definition...
  scripts/dtc/dtc-lexer.lex.o:(.bss+0x0): first defined here

    Tested on beaglebone black and beaglebone white (A6)

Signed-off-by: Lothar Felten <lothar.felten@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>

configs/beaglebone_qt5_defconfig

@@ -32,13 +32,11 @@ BR2_TARGET_ROOTFS_EXT2_SIZE="250M"
 BR2_TARGET_UBOOT=y
 BR2_TARGET_UBOOT_BUILD_SYSTEM_KCONFIG=y
 BR2_TARGET_UBOOT_CUSTOM_VERSION=y
-BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2020.04"
+BR2_TARGET_UBOOT_CUSTOM_VERSION_VALUE="2021.04"
 BR2_TARGET_UBOOT_BOARD_DEFCONFIG="am335x_evm"
 BR2_TARGET_UBOOT_NEEDS_DTC=y
 # BR2_TARGET_UBOOT_FORMAT_BIN is not set
 BR2_TARGET_UBOOT_FORMAT_IMG=y
-BR2_TARGET_UBOOT_FORMAT_CUSTOM=y
-BR2_TARGET_UBOOT_FORMAT_CUSTOM_NAME="spl/u-boot-spl.bin"
 BR2_TARGET_UBOOT_SPL=y
 BR2_TARGET_UBOOT_SPL_NAME="MLO"
 BR2_PACKAGE_HOST_DOSFSTOOLS=y