AMD's (few) graphics driver developers working on the open-source Radeon stack were unaffected by the recent layoffs and OSRC closure, while those Linux developers working on future CPU product enablement, compiler optimizations, enhancing Linux virtualization support, and other areas were the ones hit very hard.
AMD hasn't wiped out their entire Linux support staff on the CPU side but there are still developers remaining outside of the OSRC. From what I've heard from my AMD sources (keeping in mind that Phoronix has been reliably delivering exclusives on AMD Linux news for many years), the remaining Linux developers will pick up most of the slack. There won't be developers to work on "experimental" and non-core areas of support, but future CPU and chipset enablement should still be covered under Linux.
AMD Linux engineers out of India, Texas, and California will still be playing with Tux. This can already be seen with the recent GCC patches for AMD's future Steamroller CPUs (third-generation Bulldozer / bdver3). This work was largely handled by Ganesh Gopalasubramanian out of AMD India and by chance this morning he published a revised bdver3 patch.
There's still AMD developers working on Linux support, just in different areas now and there aren't as many left but AMD isn't exiting the Linux market. Linux will continue to play an important role for AMD in the server space especially with their forthcoming ARM-based Opteron products. Android will also become more important to AMD with future product launches. Linux users should certainly hope though that AMD becomes more financially fit so that it will be able to regain some of their dedicated Linux staff in the future.