neon: test for MMX/SSE instead of x86 when choosing implementation
neon: test for MMX/SSE instead of x86 when choosing implementation

On Elbrus we want to use MMX/SSE, so the old code was causing problems
on Elbrus since the code assumed that if MMX/SSE was enabled the Intel
types would be used.

nemequ/simde,nemequ/simde,nemequ/simde