net/mlx5: Fix return type mismatch in mlx5_esw_vport_vhca_id()

The function mlx5_esw_vport_vhca_id() is declared to return bool,
but returns -EOPNOTSUPP (-45), which is an int error code. This
causes a signedness bug as reported by smatch.

This patch fixes this smatch report:
drivers/net/ethernet/mellanox/mlx5/core/eswitch.h:981 mlx5_esw_vport_vhca_id()
warn: signedness bug returning '(-45)'

Fixes: 1baf30426553 ("net/mlx5: E-Switch, Set/Query hca cap via vhca id")
Reviewed-by: Parav Pandit <[e-mail]>
Signed-off-by: Zeng Chi <[e-mail]>
Reviewed-by: Tariq Toukan <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jakub Kicinski <[e-mail]>

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

···
 static inline bool
 mlx5_esw_vport_vhca_id(struct mlx5_eswitch *esw, u16 vportn, u16 *vhca_id)
 {
-	return -EOPNOTSUPP;
+	return false;
 }
 
 #endif /* CONFIG_MLX5_ESWITCH */