Bluetooth: Fix busy condition testing for EIR and class updates

The add/remove_uuid and set_dev_class mgmt commands can trigger both EIR
and class HCI commands, so testing just for a pending class command is
enough. The simplest way to monitor conflicts that should trigger "busy"
error returns is to check for any pending mgmt command that can trigger
these HCI commands. This patch adds a helper function for this
(pending_eir_or_class) and uses it instead of the old HCI_PENDING_CLASS
flag to test for busy conditions.

Signed-off-by: Johan Hedberg <johan.hedberg@intel.com>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>