iwlwifi: Fix missing error code in iwl_pci_probe()

The error code is missing in this code scenario, add the error code
'-EINVAL' to the return value 'ret'.

Eliminate the follow smatch warning:

drivers/net/wireless/intel/iwlwifi/pcie/drv.c:1376 iwl_pci_probe() warn:
missing error code 'ret'.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Fixes: 1f171f4f

 ("iwlwifi: Add support for getting rf id with blank otp")
Signed-off-by: chongjiapeng <jiapeng.chong@linux.alibaba.com>
Acked-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/1635838727-128735-1-git-send-email-jiapeng.chong@linux.alibaba.com