wil6210: drop Rx packets with L2 error indication from HW

Due to recent change in FW, driver will be notified of corrupted Rx
packets (e.g. MIC error).
Drop such packets before they are delivered to network stack.

Change-Id: I2d93908e13a55ced0d761e018d10c923382f2d32
Signed-off-by: Dedy Lansky <dlansky@codeaurora.org>
Signed-off-by: Maya Erez <merez@codeaurora.org>