The promotional material makes it clear: “Mayans M.C.” is set in a “post-Jax-Teller world.” That distinction may sound unusual, but it’s an important one. In this reboot-remake-reimagining TV landscape, the humble spin-off show has to make a strong decision about how it wants to frame itself. “Mayans M.C.” more or less picks up where “Sons of Anarchy” left off, following a motorcycle club that was not an insubstantial part of the original series. On “Sons,” the Mayans were one-time villains who ultimately became allies in the brutal dog-eat-dog-alive fictional world of creator Kurt Sutter. In bringing them back for their own series, he (alongside co-creator Elgin James) looks to recapture the magic that made “Sons,” at its best, so vital, while branching out to something new. The simple fact of an all-Latino cast is cause enough for interest, even if the show is still working on finding its voice.