qapi: Expand a few awkward abbreviations in documentation

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240322140910.328840-3-armbru@redhat.com>
diff --git a/qapi/virtio.json b/qapi/virtio.json
index 95745fd..b0cd41b 100644
--- a/qapi/virtio.json
+++ b/qapi/virtio.json
@@ -642,15 +642,17 @@
 #
 # @num: vhost_virtqueue num
 #
-# @desc-phys: vhost_virtqueue desc_phys (descriptor area phys. addr.)
+# @desc-phys: vhost_virtqueue desc_phys (descriptor area physical
+#     address)
 #
 # @desc-size: vhost_virtqueue desc_size
 #
-# @avail-phys: vhost_virtqueue avail_phys (driver area phys. addr.)
+# @avail-phys: vhost_virtqueue avail_phys (driver area physical
+#     address)
 #
 # @avail-size: vhost_virtqueue avail_size
 #
-# @used-phys: vhost_virtqueue used_phys (device area phys. addr.)
+# @used-phys: vhost_virtqueue used_phys (device area physical address)
 #
 # @used-size: vhost_virtqueue used_size
 #