This adds ARMv8 optimized string handling functions to Bionic.
The implementations live in a generic/ directory because there will
likely be more CPU specific versions (e.g. Cortex-A53 vs. Cortex-A57)
later.
These implementations are 50%+ faster on current v8 models.
Change-Id: If3adc54a284d9519459b0d4d4390f0cd6ded8786
Signed-off-by: Bernhard Rosenkraenzer <Bernhard.Rosenkranzer@linaro.org>