fix(ibmcloud): fix mapper device detection on IBM Power

lsblk -d excludes holder devices, which includes all /dev/mapper/*
devices on multipath systems. Switch to lsblk -r (raw) and detect
the data volume by finding the mpath device that has no partition
children, distinguishing it from the boot disk.

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

Author: adrianriobo

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

@@ -11,7 +11,7 @@ write_files:
       fi
       DATA_DEV=""
       while true; do
-        DATA_DEV=$(lsblk -dpno NAME,PTTYPE | awk '$2=="" && $1 ~ /\/dev\/mapper\// && $1 !~ /control/ {print $1}' | head -1)
+        DATA_DEV=$(lsblk -rnpo NAME,TYPE | awk '$2=="mpath"{mpath[$1]=1} $2=="part"{p=$1; sub(/p[0-9]+$/,"",p); has_part[p]=1} END{for(d in mpath) if(!has_part[d]&&d!~/control/) print d}' | head -1)
         [ -n "$DATA_DEV" ] && break
         udevadm trigger --subsystem-match=block 2>/dev/null || true
         udevadm settle 2>/dev/null || true