configs/solidrun_clearfog: bump kernel and bootloader

Update the kernel version to 4.17.2.

Update U-Boot version to 2018.05.

Migrate to U-Boot generic distro configuration which is easier than the
hand written boot script.

Improve the 'dd' command example in readme.txt.

Cc: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>

board/solidrun/clearfog/boot.scr.txt

@@ -1,5 +0,0 @@
-setenv fdtfile armada-388-clearfog-base.dtb
-setenv bootargs root=/dev/mmcblk0p1
-load ${devtype} ${devnum}:${distro_bootpart} ${fdt_addr_r} ${prefix}/${fdtfile}
-load ${devtype} ${devnum}:${distro_bootpart} ${kernel_addr_r} ${prefix}/zImage
-bootz ${kernel_addr_r} - ${fdt_addr_r}

board/solidrun/clearfog/extlinux.conf

@@ -0,0 +1,4 @@
+label Clearfog Linux
+  kernel /boot/zImage
+  devicetree /boot/armada-388-clearfog-base.dtb
+  append console=ttyS0,115200n8 root=/dev/mmcblk0p1 rootwait

board/solidrun/clearfog/post-build.sh

@@ -1,3 +1,5 @@
 #!/bin/sh
 
-install -m 0644 -D $BINARIES_DIR/boot.scr $TARGET_DIR/boot/boot.scr
+BOARD_DIR="$(dirname $0)"
+
+install -m 0644 -D $BOARD_DIR/extlinux.conf $TARGET_DIR/boot/extlinux/extlinux.conf

board/solidrun/clearfog/readme.txt

@@ -47,7 +47,7 @@ Buildroot prepares a bootable "sdcard.img" image in the output/images/
 directory, ready to be dumped on a microSD card. Launch the following
 command as root:
 
-  dd if=./output/images/sdcard.img of=/dev/<your-microsd-device>
+  dd if=output/images/sdcard.img of=/dev/<your-microsd-device> conv=fdatasync
 
 *** WARNING! The script will destroy all the card content. Use with care! ***