[source] brcm2708: restore /boot/config.txt before reboot

[LEDE Commits]

stintel pushed a commit to source.git, branch master:
https://git.lede-project.org/a48e5bea12911da1647a499a7b74c2408a04ac90

commit a48e5bea12911da1647a499a7b74c2408a04ac90
Author: Stijn Tintel <stijn at linux-ipv6.be>
AuthorDate: Sat Oct 21 14:51:14 2017 +0300

    brcm2708: restore /boot/config.txt before reboot
    
    The Raspberry Pi bootloader reads configuration values from config.txt
    in the boot partition. This file allows to specify the amount of memory
    to assign to the GPU, the license keys for hardware MPEG-2 and VC-1
    decoding, Device Tree parameters and overlays, and lots of other things.
    
    Since sysupgrade only restores the configuration after booting the newly
    flashed image, these values will not be active, even if sysupgrade would
    save /boot/config.txt. To solve this, add the file to the files to be
    backed up, and restore it in platform_copy_config, before reboot.
    
    Signed-off-by: Stijn Tintel <stijn at linux-ipv6.be>
---
 target/linux/brcm2708/base-files/lib/upgrade/keep.d/platform | 1 +
 target/linux/brcm2708/base-files/lib/upgrade/platform.sh     | 1 +
 2 files changed, 2 insertions(+)

diff --git a/target/linux/brcm2708/base-files/lib/upgrade/keep.d/platform b/target/linux/brcm2708/base-files/lib/upgrade/keep.d/platform
new file mode 100644
index 0000000..7867965
--- /dev/null
+++ b/target/linux/brcm2708/base-files/lib/upgrade/keep.d/platform
@@ -0,0 +1 @@
+/boot/config.txt
diff --git a/target/linux/brcm2708/base-files/lib/upgrade/platform.sh b/target/linux/brcm2708/base-files/lib/upgrade/platform.sh
index 2f2aeb0..b7613b4 100644
--- a/target/linux/brcm2708/base-files/lib/upgrade/platform.sh
+++ b/target/linux/brcm2708/base-files/lib/upgrade/platform.sh
@@ -27,6 +27,7 @@ platform_copy_config() {
 	mkdir -p /boot
 	[ -f /boot/kernel.img ] || mount -t vfat -o rw,noatime /dev/mmcblk0p1 /boot
 	cp -af "$CONF_TAR" /boot/
+	tar --directory / -xvf "$CONF_TAR" boot/config.txt
 	sync
 	umount /boot
 }