riscv64: ensure reasonable partition alignment

Currently the RISC-V preinstalled server images come with partitions that
are only 1 KiB aligned. Ext4 may use 4 KiB block size. The existing
misalignment leads to decreased performance.

Decrease the size of the loader2 partition by 34 512-byte blocks. This
results in 1 MiB alignment of the EFI and root partitions.

The remaining loader2 partition size of close to 4 MiB is still large
enough for U-Boot or a future EDK II.

Fixes: a808b28d47ec ("riscv64: build preinstalled riscv64 image with uboot SPL and CIDATA.")
Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

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

@@ -77,7 +77,7 @@ create_partitions() {
                        --new=13:34:2081 \
                        --change-name=13:loader1 \
                        --typecode=13:5B193300-FC78-40CD-8002-E86C45580B47 \
-                       --new=14:2082:10273 \
+                       --new=14:2082:10239 \
                        --change-name=14:loader2 \
                        --typecode=14:2E54B353-1271-4842-806F-E436D6AF6985 \
                        --new=15::+106M \