wil6210: remove reset file from debugfs

Reset file is not used and may cause race conditions
with operational driver if used.

Signed-off-by: Karthick Gopalasubramanian <kargop@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>