doc: update known issues with blutooth APIs

Signed-off-by: Anas Nashif <anas.nashif@intel.com>

Author: nashif

.known-issues/doc/bluetooth.conf

@@ -36,3 +36,7 @@
 ^(?P=filename):(?P=lineno): WARNING: Invalid definition: Expected end of definition. \[error at [0-9]+]
 ^.*bt_gatt_read_params.__unnamed__.*
 ^[- \t]*\^
+#
+# Bluetooth packed
+#
+^(?P<filename>[-._/\w]+/doc/api/bluetooth.rst):(?P<lineno>[0-9]+): WARNING: cpp:typeOrConcept targets a member \(__packed\).$