fix update_gpu_profile

Author: lilypan26

src/aks-preview/azext_aks_preview/agentpool_decorator.py

@@ -1648,9 +1648,10 @@ def update_gpu_profile(self, agentpool: AgentPool) -> AgentPool:
         self._ensure_agentpool(agentpool)
 
         gpu_driver = self.context.get_gpu_driver()
-        if gpu_driver is not None:
-            if agentpool.gpu_profile is None:
-                agentpool.gpu_profile = self.models.GPUProfile()
+        driver_type = self.context.get_driver_type()
+        if not agentpool.gpu_profile and (gpu_driver or driver_type):
+            agentpool.gpu_profile = self.models.GPUProfile()
+        if gpu_driver:
             agentpool.gpu_profile.driver = gpu_driver
         return agentpool