Use compiler name lookup to simplify code

Use compiler name lookup to simplify code

We don't need different names between a function and a
template. Compiler will know when use one or the other.

This let use restore original count_1s_xx() names instead of
sw_count_1s_xxx so to simplify a bit the code.

No functional change.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>