configs/olimex_a64_olinuxino: bump Linux to 6.18.8 and U-Boot to 2026.01

The patch:
* bumps Linux kernel to version 6.18.8
* bumps U-Boot to version 2026.01
* bumps ATF to version 2.14.0
* forces check hashes
* switches to extlinux

Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
[Julien: change linux.hash comment to use hash from upstream]
Signed-off-by: Julien Olivain <ju.o@free.fr>

board/olimex/a64-olinuxino/boot.cmd

@@ -1,6 +0,0 @@
-setenv bootargs console=ttyS0,115200 earlyprintk root=/dev/mmcblk0p2 rootwait
-
-fatload mmc 0 $kernel_addr_r Image
-fatload mmc 0 $fdt_addr_r sun50i-a64-olinuxino.dtb
-
-booti $kernel_addr_r - $fdt_addr_r

board/olimex/a64-olinuxino/genimage.cfg

@@ -1,15 +1,3 @@
-image boot.vfat {
-	vfat {
-		files = {
-			"Image",
-			"sun50i-a64-olinuxino.dtb",
-			"boot.scr"
-		}
-	}
-
-	size = 64M
-}
-
 image sdcard.img {
 	hdimage {
 	}
@@ -21,12 +9,6 @@ image sdcard.img {
 		size = 1032K # 1MB - 8KB + 16KB(GPT)
 	}
 
-	partition boot {
-		partition-type = 0xC
-		bootable = "true"
-		image = "boot.vfat"
-	}
-
 	partition rootfs {
 		partition-type = 0x83
 		image = "rootfs.ext4"

board/olimex/a64-olinuxino/patches/linux-headers/linux-headers.hash

@@ -0,0 +1 @@
+../linux/linux.hash

board/olimex/a64-olinuxino/patches/linux/linux.hash

@@ -0,0 +1,2 @@
+# From https://www.kernel.org/pub/linux/kernel/v6.x/sha256sums.asc
+sha256  37f0c5d5c242c1d604e87d48f08795e861a5a85f725b4ca11d0a538f12ff8cff  linux-6.18.8.tar.xz

board/olimex/a64-olinuxino/patches/uboot/uboot.hash

@@ -0,0 +1,2 @@
+# Locally calculated
+sha256  b60d5865cefdbc75da8da4156c56c458e00de75a49b80c1a2e58a96e30ad0d54  u-boot-2026.01.tar.bz2

board/olimex/a64-olinuxino/rootfs_overlay/boot/extlinux/extlinux.conf

@@ -0,0 +1,4 @@
+label A64-Olinuxino
+    kernel /boot/zImage
+    fdtdir /boot
+    append console=ttyS0,115200 root=/dev/mmcblk0p1 rootwait panic=10 ${extra}