fix: Remove UEFI booting armhf

short-term fix, as grub2 for armhf has issues. we are investigating if
we still need an armhf VM, as there is no armhf server hardware
available.

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

@@ -1,7 +1,7 @@
 #!/bin/bash -eux
 
 case $ARCH in
-    amd64|arm64|armhf|riscv64)
+    amd64|arm64|riscv64)
         ;;
     *)
         echo "We don't create EFI images for $ARCH."