iwlwifi: Add missing check for alloc_ordered_workqueue

iwlwifi: Add missing check for alloc_ordered_workqueue

[ Upstream commit 90a0d9f339960448a3acc1437a46730f975efd6a ]

Add check for the return value of alloc_ordered_workqueue since it may
return NULL pointer.

Fixes: b481de9ca074 ("[IWLWIFI]: add iwlwifi wireless drivers")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Link: https://patch.msgid.link/20230110014848.28226-1-jiasheng@iscas.ac.cn
Signed-off-by: Miri Korenblit <miriam.rachel.korenblit@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>