arm-bsp: create u-boot 2020.10 to resolve warning

Poky, etc master branches updated the u-boot recipes to use 2021.1,
causing bbappends for 2020.07 to no longer function.  Create a temporary
recipe for 2020.10 until all the BSPs can update to support the latest
version.

Change-Id: I6046b420a8d0b3cc2125004444683ecd51f3499b
Signed-off-by: Jon Mason <jon.mason@arm.com>

meta-arm-bsp/recipes-bsp/u-boot/u-boot_2020.10.bb

@@ -0,0 +1,26 @@
+HOMEPAGE = "http://www.denx.de/wiki/U-Boot/WebHome"
+DESCRIPTION = "U-Boot, a boot loader for Embedded boards based on PowerPC, \
+ARM, MIPS and several other processors, which can be installed in a boot \
+ROM and used to initialize and test the hardware or to download and run \
+application code."
+SECTION = "bootloaders"
+DEPENDS += "flex-native bison-native"
+
+LICENSE = "GPLv2+"
+LIC_FILES_CHKSUM = "file://Licenses/README;md5=5a7450c57ffe5ae63fd732446b988025"
+PE = "1"
+
+# We use the revision in order to avoid having to fetch it from the
+# repo during parse
+SRCREV = "050acee119b3757fee3bd128f55d720fdd9bb890"
+
+SRC_URI = "git://git.denx.de/u-boot.git \
+          "
+
+S = "${WORKDIR}/git"
+B = "${WORKDIR}/build"
+do_configure[cleandirs] = "${B}"
+
+require recipes-bsp/u-boot/u-boot.inc
+
+DEPENDS += "bc-native dtc-native"