firmware: fix wrong memory deallocation in fw_add_devm_name()

Device resource data allocated with devres_alloc() must be deallocated
by devres_free().

Signed-off-by: Vladimir Zapolskiy <vz@mleia.com>
Acked-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>