VP8LDoFillBitWindow: support big-endian in fast path
VP8LDoFillBitWindow: support big-endian in fast path

Change-Id: I577944fe0b85505766050dba5ab5aec48b30f541

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