fix(ibmcloud): settle udev before mkfs on IBM Power data volume

Add udevadm settle + 10s pause between device detection and mkfs.xfs
to let multipathd finish internal bookkeeping after the mapper device
first becomes visible.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: adrianriobo

pkg/provider/ibmcloud/action/ibm-power/cloud-config

@@ -18,6 +18,8 @@ write_files:
         multipathd reconfigure 2>/dev/null || true
         sleep 10
       done
+      udevadm settle 2>/dev/null || true
+      sleep 10
       mkfs.xfs -f -K "$DATA_DEV"
       UUID=$(blkid -s UUID -o value "$DATA_DEV")
       mkdir -p /mnt/home-tmp