net/mlx5e: Slightly increase RX page-cache size

In XDP_TX flow, we now get back quicker to each page in page-cache,
and on some occasions refcount does not get back to 1 on time, causing
some costly page allocations.
Slightly increase the size of RX page-cache to significantly decrease
the chances for this to happen.
Signed-off-by: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/en.h

@@ -501,7 +501,7 @@ struct mlx5e_rx_am { /* Adaptive Moderation */
  */
 #define MLX5E_CACHE_UNIT	(MLX5_MPWRQ_PAGES_PER_WQE > NAPI_POLL_WEIGHT ? \
 				 MLX5_MPWRQ_PAGES_PER_WQE : NAPI_POLL_WEIGHT)
-#define MLX5E_CACHE_SIZE	(2 * roundup_pow_of_two(MLX5E_CACHE_UNIT))
+#define MLX5E_CACHE_SIZE	(4 * roundup_pow_of_two(MLX5E_CACHE_UNIT))
 struct mlx5e_page_cache {
 	u32 head;
 	u32 tail;