mwifiex: correction in mwifiex_check_fw_status() return status

For PCIe cards, when wrong firmware is downloaded, firmware is
failed to be ready in 10 seconds. We should return an error at
this point. But currently we are sending first command to firmware.
As expected firmware doesn't respond to this command and command
timeout occurs.

This patch fixes the problem by removing unnecessary 'ret'
variable modifications in "if (ret) {" block.
The block is just supposed to update "adapter->winner" flag.

Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>