Fixes #2781: Fixes filter by regions on site and device list

* Add Device filter

netbox/tenancy/forms.py

@@ -115,6 +115,34 @@ class TenantFilterForm(BootstrapMixin, CustomFieldFilterForm):
         )
     )
 
+#
+# Tenancy filtering form extension
+#
+class TenancyFilterForm(forms.Form):
+    tenant_group = FilterChoiceField(
+        queryset=TenantGroup.objects.all(),
+        to_field_name='slug',
+        null_label='-- None --',
+        widget=APISelectMultiple(
+            api_url="/api/tenancy/tenant-groups/",
+            value_field="slug",
+            null_option=True,
+            filter_for={
+                'tenant': 'group'
+            }
+        )
+    )
+    tenant = FilterChoiceField(
+        queryset=Tenant.objects.all(),
+        to_field_name='slug',
+        null_label='-- None --',
+        widget=APISelectMultiple(
+            api_url="/api/tenancy/tenants/",
+            value_field="slug",
+            null_option=True,
+        )
+    )
+
 
 #
 # Tenancy form extension