wil6210: fix break that is never reached because of zero'ing of a retry counter

There is a check on the retry counter invalid_buf_id_retry that is always
false because invalid_buf_id_retry is initialized to zero on each iteration
of a while-loop.  Fix this by initializing the retry counter before the
while-loop starts.

Addresses-Coverity: ("Logically dead code")
Fixes: b4a967b7

 ("wil6210: reset buff id in status message after completion")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reviewed-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>