riscv64: use efi=debug earlycon

RISC-V boards tend to boot slowly.
We should provide progress information when booting.

Use 'efi=debug earlycon' on the Linux command line via new file
/etc/default/grub.d/cmdline.cfg.

Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

live-build/ubuntu-cpc/hooks.d/base/disk-image-uefi.binary

@@ -240,6 +240,10 @@ install_grub() {
             # TODO grub-efi-riscv64 exists, but is not used by all the images yet
             if [ -n "${SUBARCH:-}" ]; then
                 # Per-device images
+                local my_d=$(dirname $(readlink -f ${0}))
+                echo "Adjusting GRUB defaults for ${ARCH}"
+                mkdir -p mountpoint/etc/default/grub.d/
+                cp ${my_d}/riscv64/grub/cmdline.cfg mountpoint/etc/default/grub.d/
                 case "${SUBARCH}" in
                     "icicle")
                         echo "Installing GRUB for ${SUBARCH} board"
@@ -271,7 +275,6 @@ install_grub() {
                         chroot mountpoint rm -f /boot/boot.scr
                         ;;
                     "nezha"|"licheerv")
-                        local my_d=$(dirname $(readlink -f ${0}))
                         echo "Reducing initramfs size for ${SUBARCH} board"
                         mkdir -p mountpoint/etc/initramfs-tools/conf.d/
                         cp ${my_d}/riscv64/initramfs-tools/modules_list.conf mountpoint/etc/initramfs-tools/conf.d/

live-build/ubuntu-cpc/hooks.d/base/riscv64/grub/cmdline.cfg

@@ -0,0 +1,4 @@
+# Booting on many riscv64 systems is slow. Let the user view progress.
+# For minimum output use
+# GRUB_CMDLINE_LINUX_DEFAULT="quiet"
+GRUB_CMDLINE_LINUX_DEFAULT="efi=debug earlycon"