Bluetooth: mgmt: Fix the command returns garbage parameter value

[ Upstream commit 02ce2c2c

 ]

When the Get Device Flags command fails, it returns the error status
with the parameters filled with the garbage values. Although the
parameters are not used, it is better to fill with zero than the random
values.

Signed-off-by: Tedd Ho-Jeong An <tedd.an@intel.com>
Signed-off-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>