wil6210: remove fake support for RXHASH

Setting the same fake hash to all skbs prevents
distributing different flows to different CPU cores.

Signed-off-by: Hamad Kadmany <hkadmany@codeaurora.org>
Signed-off-by: Lior David <liord@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>