cxgb4: Fix some small bugs in t4_sge_init_soft() when our Page Size is 64KB

We'd come in with SGE_FL_BUFFER_SIZE[0] and [1] both equal to 64KB and the
extant logic would flag that as an error.

Based on original work by Casey Leedom <leedom@chelsio.com>
Signed-off-by: NKumar Sanghvi <kumaras@chelsio.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/ethernet/chelsio/cxgb4/sge.c

@@ -2596,11 +2596,19 @@ static int t4_sge_init_soft(struct adapter *adap)
 	fl_small_mtu = READ_FL_BUF(RX_SMALL_MTU_BUF);
 	fl_large_mtu = READ_FL_BUF(RX_LARGE_MTU_BUF);
 
+	/* We only bother using the Large Page logic if the Large Page Buffer
+	 * is larger than our Page Size Buffer.
+	 */
+	if (fl_large_pg <= fl_small_pg)
+		fl_large_pg = 0;
+
 	#undef READ_FL_BUF
 
+	/* The Page Size Buffer must be exactly equal to our Page Size and the
+	 * Large Page Size Buffer should be 0 (per above) or a power of 2.
+	 */
 	if (fl_small_pg != PAGE_SIZE ||
-	    (fl_large_pg != 0 && (fl_large_pg < fl_small_pg ||
-				  (fl_large_pg & (fl_large_pg-1)) != 0))) {
+	    (fl_large_pg & (fl_large_pg-1)) != 0) {
 		dev_err(adap->pdev_dev, "bad SGE FL page buffer sizes [%d, %d]\n",
 			fl_small_pg, fl_large_pg);
 		return -EINVAL;