riscv: Bump image size to 4.5G

3.5G is not enough for riscv64 preinstalled as the creation of the initrd fails
with the following error:

Creating config file /etc/default/grub with new version
Processing triggers for initramfs-tools (0.140ubuntu13) ...
update-initramfs: Generating /boot/initrd.img-5.15.0-1011-generic
zstd: error 25 : Write error : No space left on device (cannot write compressed block)
E: mkinitramfs failure zstd -q -1 -T0 25
update-initramfs: failed for /boot/initrd.img-5.15.0-1011-generic with 1.
dpkg: error processing package initramfs-tools (--configure):
 installed initramfs-tools package post-installation script subprocess returned error exit status 1

Signed-off-by: Alexandre Ghiti <alexandre.ghiti@canonical.com>

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

@@ -25,13 +25,17 @@ if [ "$ARCH" = "armhf" ]; then
     IMAGE_SIZE=3758096384 # bump to 3.5G (3584*1024**2); Since Jammy armhf need more then the default 2.2G
 fi
 
-# Change image size for preinstalled generic images & all preinstalled riscv64 images
+# Change image size for preinstalled generic images
 if [ -n "${SUBARCH:-}" ]; then
-    if [ "${SUBARCH:-}" = "generic" ] || [ "$ARCH" = "riscv64" ]; then
+    if [ "${SUBARCH:-}" = "generic" ]; then
         IMAGE_SIZE=3758096384 # bump to 3.5G (3584*1024**2), due to linux-generic instead of virtual
 fi
 fi
 
+if [ "$ARCH" = "riscv64" ]; then
+    IMAGE_SIZE=4831838208 # bump to 4.5G (4608*1024**2); initrd creation fails with "No space left" with 3.5G
+fi
+
 . config/binary
 
 . config/functions