bionic: Optimizations for gettimeofday and clock_gettime.

Use the kernel user helper feature to calculate the results
of gettimeofday and clock_gettime without actually calling
into kernel space. If the user helper patches have not been
applied to the kernel, the regular system calls are used as
a fallback.

Change-Id: I3aebc6ac19ab4743725648a1a279819e624cc5c4
Fix perf regression on Cortex A15 by optimized memcpy for Cortex A9

The new Cortex A9 optimized memcpy included an arm-only version that is
slower than the current neon Cortex A15. This arm-only version was used
when the dst was aligned to an 8 byte boundary, otherwise, the original
neon only version was used. This change modifies the code so it always
uses the neon only version for the Cortex A15. It also fixes the use of
a define removed with the previous optimization.

Change-Id: I971527568a177218cd8b76a8bd160aaaf6ea1e42
Fix typo