u-boot: Convert ${UBOOT_ENV}.cmd into ${UBOOT_ENV}.scr

* Add extra SRC variables to uboot-config.class for source cmd file
 * Add DEPENDS on u-boot-mkimage-native if UBOOT_ENV_SUFFIX is scr
 * Compile cmd -> scr in do_compile if UBOOT_ENV_SUFFIX is scr

(From OE-Core rev: 0ea02ca5c1fc4e15f640b1c26c0a5ce34fc08c05)

Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/classes/uboot-config.bbclass

@@ -53,6 +53,8 @@ SPL_SYMLINK ?= "${SPL_BINARYNAME}-${MACHINE}${SPL_DELIMITER}${SPL_SUFFIX}"
 # include it in the SRC_URI and set the UBOOT_ENV parameter.
 UBOOT_ENV_SUFFIX ?= "txt"
 UBOOT_ENV ?= ""
+UBOOT_ENV_SRC_SUFFIX ?= "cmd"
+UBOOT_ENV_SRC ?= "${UBOOT_ENV}.${UBOOT_ENV_SRC_SUFFIX}"
 UBOOT_ENV_BINARY ?= "${UBOOT_ENV}.${UBOOT_ENV_SUFFIX}"
 UBOOT_ENV_IMAGE ?= "${UBOOT_ENV}-${MACHINE}-${PV}-${PR}.${UBOOT_ENV_SUFFIX}"
 UBOOT_ENV_SYMLINK ?= "${UBOOT_ENV}-${MACHINE}.${UBOOT_ENV_SUFFIX}"

meta/recipes-bsp/u-boot/u-boot.inc

@@ -4,6 +4,7 @@ PROVIDES = "virtual/bootloader"
 PACKAGE_ARCH = "${MACHINE_ARCH}"
 
 DEPENDS += "kern-tools-native"
+DEPENDS += "${@bb.utils.contains('UBOOT_ENV_SUFFIX', 'scr', 'u-boot-mkimage-native', '', d)}"
 
 inherit uboot-config uboot-extlinux-config uboot-sign deploy cml1 python3native kernel-arch
 
@@ -106,6 +107,11 @@ do_compile () {
             oe_runmake -C ${S} O=${B} u-boot-initial-env
         fi
     fi
+
+    if [ -n "${UBOOT_ENV}" && "${UBOOT_ENV_SUFFIX}" = "scr" ]
+    then
+        ${UBOOT_MKIMAGE} -C none -A ${UBOOT_ARCH} -T script -d ${WORKDIR}/${UBOOT_ENV_SRC} ${WORKDIR}/${UBOOT_ENV_BINARY}
+    fi
 }
 
 do_install () {