create_custom_esxi_iso.ps1: Print base image path correctly

[jthat]

$ESXIDriver is undefined. It should be $ESXIBaseImagePath.

Example output difference:

 PS C:\users\jason\desktop\custom-esxi-image> .\create_custom_esxi_iso.ps1
-Processing ESXi Base Image  ...
+Processing ESXi Base Image C:\Users\jason\Desktop\custom-esxi-image\VMware-ESXi-7.0U3c-19193900-depot.zip ...
 Processing ESXi Driver C:\Users\jason\Desktop\custom-esxi-image\Net-Community-Driver_1.2.7.0-1vmw.700.1.0.15843807_19480755.zip ...
 Processing ESXi Driver C:\Users\jason\Desktop\custom-esxi-image\nvme-community-driver_1.0.1.0-3vmw.700.1.0.15843807-component-18902434.zip ...