So since for ever AMD basically picks up Intels scraps, Intel gets a market and AMD get X% of it where X is dependent on how good the AMD chip is, but is always a pretty small %. This is just the way it is.
The problem here is that Intel's tablet market isn't very big because unlike x86 Intel has to compete with all the ARM vendors and they dominate the market, even with Intel's deep pockets, manufacturing advantages and all the rest. Hence realistically all AMD is going to get is a small % of what Intel gets, which isn't very much, so it is highly likely AMD will make very few sales.
What AMD need to do is find something specialist like the console market where other vendors have trouble going - a competitor to nvidia's grid for remote gaming and rendering might be good. That said the online server market is being infiltrated by ARM and power pc variants - the big vendors (amazon, google, etc) are seriously considering making their own hardware, and they could also make grid like solutions. Even in comparison to a few years ago when AMD won console bids, ARM based cpu + gpu capabilities have come along way - no guarantees AMD could even win that today, it's just a highly competitive place to be.