qcacmn: WAR for duplicate RX desc issue from REO2SW ring

Two back to back same RX desc is received from
REO2SW1 ring. After first RX desc is processed,
RX_desc nbuf will be set to null.
when second REO entry/same RX desc is processing,
dp_rx_desc_nbuf_sanity_check() will access to RX_desc nbuf, null
nbuf accessing lead to panic.

As a WAR, check RX_desc in_use flag firstly to avoid
invalid accessing to nbuf, move
dp_rx_desc_nbuf_sanity_check() after it.

Change-Id: Ib9455c76af85cf83587c1428b20a9ad9e93a9499
CRs-Fixed: 2672088