west.yml: hal_ambiq: Add Bluetooth support.

Imported the original Cooper (Apollo4x BLE controller) device files
from AmbiqSuite SDK 4.4.0 and adapts them to support the new
implemented HCI driver for Apollo4 Blue Plus.

Signed-off-by: Aaron Ye <aye@ambiq.com>

west.yml

@@ -142,7 +142,7 @@ manifest:
       groups:
         - hal
     - name: hal_ambiq
-      revision: 0c5ea5749245c8ff6ce7aefbf0aa9981943c2857
+      revision: pull/9/head
       path: modules/hal/ambiq
       groups:
         - hal