You would have to have a speed boost Torchic to breed it and pass down speed boost. Pokémon with normal abilities only pass down normal abilities and a HA Torchic, combusken, or blaziken has a %60 chance of passing speed boost down to its offspring. You can not breed mega blaziken because mega evolution can only occur during battle. If you don’t have a HA Torchic, cumbusken, or blaziken, it will be hard to get one. They are rare.