Add non-overfetching ARM-optimized assembler memcpy routine

Add a non-overfetching version of the memcpy_armv5te function that does
not do preload beyond the source region. Also add possible optimization
to the inner loops of memcpy_armv5te_non_overfetched (this possible
optimization has not been applied to the original memcpy_armv5te).

The non over-fetching version show strong performance improvements on the
Allwinner platform for some common parameters, such as randomly aligned
small sizes from 20 up to a few hundred bytes.
Update benchmark program with non-overfetching memcpy

Update the benchmark program to also show results for
memcpy_armv5te_non_overfetched. Update sample results for the
Allwinner platform.