I have addressed this issue as an example of some of the fraught problems with the Pathfinder FAQ, here:
Mounted charges and action usage—Another outright rules change, this one completely breaks mounted combat. It says that the rider needs to use the charge action him-or-herself in order to charge while mounted—but that is a full-round action, and ordering a mount to do anything requires a move action. Very few characters can spend a move action and then still have a full-round action available. Realistically, the only way to charge here is to have a special bond to your mount (e.g. as with druids, paladins, and rangers), so that you don’t need to spend the move action to order the mount.
Note also that this FAQ entry promises that future printings of the CRB will be updated to reflect it. That was four years ago, and it hasn’t happened yet. That means for four years the last word on the subject has broken the functionality completely for most characters, and there has been no update, reprinting, or errata to address it. A great example of how having an FAQ reduces errata and how that can be very bad.
Finally, this chat room was created to discuss this issue, if you want more detail.
In D&D 3.5e and in Pathfinder prior to this FAQ, a mounted combatant didn’t use the same action that the mount itself did. That meant the mounted character could spend a move action getting the mount to charge, the mount could spend a full-round action charging, and the mounted character still had a standard action which was subsumed into making the attack at the end of the charge. To be honest, the rules really did get kind of fuzzy on how that worked—the community had a pretty clear consensus on it, so for example it was a charge attack at the end for the mounted character, and not a regular attack e.g. for Vital Strike, but the rules weren’t really explicit about saying that. So an errata clearing these things up was totally appropriate—but this FAQ was absolutely not the change that was needed.
Because, basically, whoever answered the FAQ appear to have forgot that people other than rangers and paladins sometimes ride mounts. Or they forgot that, for those people, an extra move action is required to get your mount to do anything. Or... or to be honest, I don’t really know what they were thinking. The FAQ is incredibly bad. It literally breaks mounted charges, one of the most iconic maneuvers in the narrative precedent, for almost all characters.
Unfortunately, the Pathfinder FAQ is official. It is supposed to be followed, according to Paizo. I think any GM ever would ignore that, at least in this case, but in some situations they can’t—for example, Pathfinder Society GMs really are supposed to stick to playing “by the book.” And by the book, you can’t charge without a special companion mount.
But at your own games, ignore this nonsense. It’s one of the worst FAQ entries in the system, it almost-certainly wasn’t intended (though Paizo is rarely willing to admit they make such mistakes, so it hasn’t been corrected), and it definitely does not add to the game. The core rules were somewhat lacking on the subject of mounted combat, but being unclear is still superior to being clearly wrong.