configure: unconditionally check for atomic ops/primitives

Just have the check once, and let new drivers opt-in if they want
to use them. Move the block further up the script, to tie nicely
with the actual usage of $HW defines.

Move the final $HW users to be alongside their brethren.

Signed-off-by: Emil Velikov <emil.l.velikov@gmail.com>
Reviewed-by: Jakob Bornecrantz <jakob@vmware.com>