In binfmt_flat.c, the flat binary loader should check file descriptor table
and install the fd on the file.

Convert the function to single-exit and fix this bug.
Signed-off-by: "Luke Yang" <luke.adi@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>