Clean up redundant flags with O3

  * Add some memory optimizations
  * Remove some redundant/unneeded lags
  * Switch to -mfpu neon-vfpv4 as krait has neon and vfpv4 capabilities

Change-Id: I28710cc2d7b11e007713fe8f610778efaff95d38
Signed-off-by: Josue Rivera <prbassplayer@gmail.com>