DC{4,8,16}_NEON: replace vmovl w/vaddl
DC{4,8,16}_NEON: replace vmovl w/vaddl

4/8/16 fewer instructions

Change-Id: I38fe08722e7b839e3f3e0bf4df7e0fa8e7a0138f

PKRoma/libwebp,webmproject/libwebp,webmproject/libwebp,webmproject/libwebp,PKRoma/libwebp,webmproject/libwebp,PKRoma/libwebp,PKRoma/libwebp,PKRoma/libwebp,PKRoma/libwebp,webmproject/libwebp