wil6210: missing reinit_completion in wmi_call

The code in wmi_call uses the wil->wmi_call completion
structure to wait for a reply.
In some scenarios, complete was called twice on the
completion structure. This happened mainly with a disconnect
event which can arrive both unsolicited and as a reply to
a disconnect request. In this case the completion structure
was left marked as "done" and the next wmi_call returned
immediately with a corrupted reply buffer. This caused
unexpected results including crashes.
Fix this by adding the missing call to reinit_completion.

Signed-off-by: Lior David <qca_liord@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>