1) Login to VIO as padmin
2) Run the command oem_setup_env to gain root privilege

Run the script:
for hdsk in `/usr/ios/cli/ioscli lsmap -vadapter vhost3 |grep Backing |awk ‘{print $NF}’`
do
max_transfer=`lsattr -El $hdsk |grep max_transfer`
echo $hdsk $max_transfer
done

I below got this:
hdisk50 max_transfer 0x100000 Maximum TRANSFER Size True
hdisk51 max_transfer 0x100000 Maximum TRANSFER Size True
hdisk52 max_transfer 0x100000 Maximum TRANSFER Size True
hdisk53 max_transfer 0x40000 Maximum TRANSFER Size True
hdisk54 max_transfer 0x40000 Maximum TRANSFER Size True
hdisk55 max_transfer 0x100000 Maximum TRANSFER Size True
hdisk56 max_transfer 0x100000 Maximum TRANSFER Size True
hdisk57 max_transfer 0x100000 Maximum TRANSFER Size True
hdisk58 max_transfer 0x100000 Maximum TRANSFER Size True

Therefore, I was able to figure out that problem was coming from two disks which had different max_transfer size
I have removed the newly created VTDs and changed the attribute of the disks as shown below

chdev -l hdiskx -a max_transfer=0x100000

After this I was able to create the VTD and see it on the target LPAR without rebooting the it