wil6210: make sure Rx ring sizes are correlated

commit 61e5ec044748486f06dec760a19dce78247b3ad8 upstream.

When enlarging rx_ring_order module param, wil6210 fails to load
because there are not enough Rx buffers.
Fix this by enlarging number of Rx buffers at startup, if needed based
on rx_ring_order.

Signed-off-by: Dedy Lansky <dlansky@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>