This is quite simple in PowerCLI, you just combine 2 cmdlets with a pipeline.
Get-VM | Update-Tools
You can make the selection of the guests a bit more complex.
For example:
Get-VM -Name Srv* | Update-Tools
will only update the tools on guests whose name starts with SRV.
See the Get-VM cmdlet for more details.
You can also define it the tools update should reboot immediatly if required.
This you can do with the NoReboot parameter on the Update-Tools cmdlet.
Get-VM -Name Srv* | Update-Tools -NoReboot