lib/blkid: remove 32-bit x86 byteswap assembly

lib/blkid: remove 32-bit x86 byteswap assembly

libblkid contains 32-bit x86 assembly language implementations of 16-bit
and 32-bit byteswaps.  However, modern compilers can easily generate the
bswap instruction automatically from the corresponding C expression.
And no one ever bothered to add assembly for x86_64 or other
architectures, anyway.  So let's just remove this outdated code, which
was maybe useful in the 90s, but is no longer useful.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>