webpinfo: fix fourcc comparison w/big-endian
webpinfo: fix fourcc comparison w/big-endian

store the recognized fourccs in little-endian order to match how the
fourcc is being read from the file

Bug: webp:548
Change-Id: I9de77db92208709d5e711846908a51e563102fa5
(cherry picked from commit e3cb052ca5172e02641e8211ab1701bfa20d4c7d)

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