wil6210: Align Rx frames on 4*n+2 by having SNAP

For the networking code and for hardware network accelerators,
it is better to have IP header 4*n aligned. On the other side,
DMA on Rx path require buffer to be aligned on 4*n as well.
Having 14 bytes of Ethernet header, these 2 alignment
requests are in contradiction.

To solve this, order hardware offload block to not remove
SNAP header. This adds extra 6 bytes between addresses and
ethertype, making it 20 bytes total. This way, both buffer and
IP header are 4*n aligned. Remaining is only to remove SNAP
by shifting addresses 6 bytes. This involves data copying, so
this feature should be disabled unless required by the platform.

Module parameter "rx_align_2" (bool, default - false)
introduced to control this feature. Feature is completely disabled
when parameter is false.

Signed-off-by: Vladimir Kondratiev <qca_vkondrat@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/drivers/net/wireless/ath/wil6210/wil6210.h b/drivers/net/wireless/ath/wil6210/wil6210.h
index c1a71ab..a6b096e 100644
--- a/drivers/net/wireless/ath/wil6210/wil6210.h
+++ b/drivers/net/wireless/ath/wil6210/wil6210.h
@@ -28,6 +28,7 @@
 extern unsigned short rx_ring_overflow_thrsh;
 extern int agg_wsize;
 extern u32 vring_idle_trsh;
+extern bool rx_align_2;
 
 #define WIL_NAME "wil6210"
 #define WIL_FW_NAME "wil6210.fw" /* code */