dcbnl : Fix misleading dcb_app->priority explanation

Current explanation of dcb_app->priority is wrong. It says priority is
expected to be a 3-bit unsigned integer which is only true when working with
DCBx-IEEE. Use of dcb_app->priority by DCBx-CEE expects it to be 802.1p user
priority bitmap. Updated accordingly

This affects the cxgb4 driver, but I will post those changes as part of a
larger changeset shortly.

Fixes: 3e29027af4372 ("dcbnl: add support for ieee8021Qaz attributes")
Signed-off-by: Anish Bhatt <anish@chelsio.com>
Acked-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/uapi/linux/dcbnl.h b/include/uapi/linux/dcbnl.h
index 6bb4338..e711f20 100644
--- a/include/uapi/linux/dcbnl.h
+++ b/include/uapi/linux/dcbnl.h
@@ -148,7 +148,8 @@
  *
  * @selector: protocol identifier type
  * @protocol: protocol of type indicated
- * @priority: 3-bit unsigned integer indicating priority
+ * @priority: 3-bit unsigned integer indicating priority for IEEE
+ *            8-bit 802.1p user priority bitmap for CEE
  *
  * ----
  *  Selector field values