fs/affs/file.c: fix shadow warnings

Four functions declared variables twice resulting in shadow warnings.

This patch renames internal variables and adds blank line after
declarations.

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>