This patch adds common nls_tolower, nls_toupper and nls_strnicmp helpers to
nls.h and uses them in various filesystems instead of local duplicates.

The situation for ncpfs isn't as nice as it allows to compile without nls
support even if the kernel has CONFIG_NLS set, so we need wrappers there.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>