Update xcp-prepare-windows-for-xcp-smb.adoc

[SuperJT]

the verbage used initially sounds like we need to add the user to the builtin administrators group on the xcp server. this is not true, we need to add the user to the builtin administrators group on the target svm

[netapp-pcarriga]

Hi @SuperJT, thank you for providing this feedback. We will verify and update the documentation accordingly.

[netapp-cgoff]

Hi, thanks again for raising this issue. This has now been addressed in our documentation here: Prepare Windows for XCP SMB