Azure/Travis: Re-sync jobs and clarify exclusions

We keep both of these jobs in sync as much as possible even when the
primary motivation is to keep Travis from exceeding the build time limit
there.  With that in mind:
- Use "rk" not "rockchip" to get all Rockchip SoC platforms in one job,
  rather than just all Rockchip vendor platforms.
- The NXP LX216* SoCs have their own job, exclude them from the AArch64
  generic job.
- SoCFPGA SoCs have their own job, exclude them from the AArch64 generic
  job.

Signed-off-by: Tom Rini <trini@konsulko.com>