net/mlx5: Delete unused FPGA QPN variable

fpga_qpn was assigned but never used and compilation with W=1
produced the following warning:

drivers/net/ethernet/mellanox/mlx5/core/fpga/core.c: In function _mlx5_fpga_event_:
drivers/net/ethernet/mellanox/mlx5/core/fpga/core.c:320:6: warning:
variable _fpga_qpn_ set but not used [-Wunused-but-set-variable]
  u32 fpga_qpn;
      ^~~~~~~~

Fixes: 98db16ba ("net/mlx5: FPGA, Handle QP error event")
Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Saeed Mahameed <saeedm@mellanox.com>

drivers/net/ethernet/mellanox/mlx5/core/fpga/core.c

@@ -317,7 +317,6 @@ static int mlx5_fpga_event(struct mlx5_fpga_device *fdev,
 	const char *event_name;
 	bool teardown = false;
 	unsigned long flags;
-	u32 fpga_qpn;
 	u8 syndrome;
 
 	switch (event) {
@@ -328,7 +327,6 @@ static int mlx5_fpga_event(struct mlx5_fpga_device *fdev,
 	case MLX5_EVENT_TYPE_FPGA_QP_ERROR:
 		syndrome = MLX5_GET(fpga_qp_error_event, data, syndrome);
 		event_name = mlx5_fpga_qp_syndrome_to_string(syndrome);
-		fpga_qpn = MLX5_GET(fpga_qp_error_event, data, fpga_qpn);
 		break;
 	default:
 		return NOTIFY_DONE;