Spectre should be fixed with the update Tuesday (assuming LOS backports these fixes which is a fair bet). You can verify by checking patch level at Settings -> About phone -> Android security patch level. Should be as Ingo stated after Tuesday.
Meltdown, as far as its known today, only affects Intel and a few rare ARM processors: Cortex-A15, Cortex-A57, Cortex-A72. Snapdragon 810 is based on A57. FP2 is a Snapdragon 800 though.
See this article for current information and which hardware is affected:
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