gdb/tui: update maybe_update to take gdbarch

gdb/tui: update maybe_update to take gdbarch

This is a refactor to setup for the next commit.

The maybe_update function currently takes a frame_info_ptr&, however,
it only uses this to get the frame's gdbarch.

In the next commit I want to call maybe_update when I have a gdbarch,
but no frame_info_ptr& (the inferior hasn't even started).

So, update maybe_update to take the gdbarch, and update the callers to
pass that through.  Most callers already have the gdbarch to hand, but
in one place I do need to extract this from the frame_info_ptr&.

There should be no user visible changes after this commit.

Approved-By: Tom Tromey <tom@tromey.com>