osi: dma: using swcx to store nvsocket rx data idx

- Added a data_idx field in rx swcx to store nvsocket data index.
  Tx data idx has been added in a earlier commit.

Jira NET-242

Change-Id: I81e4c41efceabab4dbf556ac3f57ca26e0737a81
Signed-off-by: Zhongjie Wang <zhowang@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/c/kernel/nvethernetrm/+/2778530
Reviewed-by: svcacv <svcacv@nvidia.com>
Reviewed-by: Ajay Gupta <ajayg@nvidia.com>
Reviewed-by: Srinivas Ramachandran <srinivasra@nvidia.com>
GVS: Gerrit_Virtual_Submit <buildbot_gerritrpt@nvidia.com>

include/osi_dma.h

@@ -327,6 +327,8 @@ struct osi_rx_swcx {
 	nveu32_t len;
 	/** Flags to share info about Rx swcx between OSD and OSI */
 	nveu32_t flags;
+	/** nvsocket data index */
+	nveu64_t data_idx;
 };
 
 /**