Update available-regions-skus.md

Adding AN64 in North Central US per Mike Weiner. Nutanix has confirmed the nodes are qualified and enabled in prod.

Author: chris-fagan

articles/baremetal-infrastructure/workloads/nc2-on-azure/available-regions-skus.md

@@ -47,7 +47,7 @@ When planning your NC2 on Azure design, use the following table to understand wh
 | East US 2 | AN36P, AN64 |
 | Germany West Central | AN36P, AN64 |
 | Japan East | AN36P |
-| North Central US | AN36P |
+| North Central US | AN36P, AN64 |
 | Qatar Central | AN36P |
 | Southeast Asia | AN36P |
 | South India | AN36P |