wcn36xx: Wait longer for SMD commands to complete

On some wcnss firmwares the start command can take up to 300ms to
complete. Currently there is a 200ms timeout for SMD command to
complete which causes the start to fail.

Increase the timeout to 500ms. Also improve debug information
regarding SMD command completion time.

Signed-off-by: Pontus Fuchs <pontus.fuchs@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>