fs/bio.c: move EXPORT* macros to line after function

As mentioned in Documentation/CodingStyle, move EXPORT* macro's
to the line immediately after the closing function brace line.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>