libubootenv_%.bbappend: Add fw_env.config

Add fw_env.config that uses at run-time /boot/uboot.env generated
through the boot scripts (specifically boot.cmd.in) from recipe
rpi-u-boot-scr. This configuration file is required to
successfully run fw_printenv from the user space.

Signed-off-by: Leon Anavi <leon.anavi@konsulko.com>
Signed-off-by: Khem Raj <raj.khem@gmail.com>

recipes-bsp/u-boot/files/fw_env.config

@@ -0,0 +1 @@
+/boot/uboot.env 0x0000    0x4000

recipes-bsp/u-boot/libubootenv_%.bbappend

@@ -0,0 +1,12 @@
+FILESEXTRAPATHS_prepend := "${THISDIR}/files:"
+
+SRC_URI_append_rpi = " \
+    file://fw_env.config \
+"
+
+DEPENDS_append_rpi = " rpi-u-boot-scr"
+
+do_install_append_rpi () {
+    install -d ${D}${sysconfdir}
+    install -m 0644 ${WORKDIR}/fw_env.config ${D}${sysconfdir}/fw_env.config
+}