mwifiex: use separate wait condition for each command node

Currently global wait condition (adapter->cmd_wait_q.condition)
is used while sending synchronous commands to FW. When two threads
enter in mwifiex_send_cmd_sync() routine at the same time, both the
threads wait for their command responses. Since wait condition is
same for both, they wake up simultaneously after getting response
of 1st command. After this when a thread is waiting for command
response of 3rd command, it wakes up after getting response of 2nd
command and so on. Therefore we don't wait for the response of last
command(0xaa) during unload. Hence while next time loading the driver
command time out is seen for INIT command.

This problem is resolved by having separate wait condition flag for
each command(except scan command). Since scan command is treated
differently (by maintaining scan pending q etc.), newly defined flag
(scan_wait_q_woken) is used as a scan wait condition.

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