staging: lustre: declare fiemap_for_stripe static

Declare fiemap_for_stripe as static to fix sparse warnings:

> warning: symbol 'fiemap_for_stripe' was not declared. Should it be
> static?
Signed-off-by: David Wittman <dwittman@gmail.com>
Acked-by: James Simmons <jsimmons@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/lustre/lustre/lov/lov_object.c

@@ -1141,7 +1141,7 @@ struct fiemap_state {
 	bool		fs_enough;
 };
 
-int fiemap_for_stripe(const struct lu_env *env, struct cl_object *obj,
+static int fiemap_for_stripe(const struct lu_env *env, struct cl_object *obj,
 			     struct lov_stripe_md *lsm,
 			     struct fiemap *fiemap, size_t *buflen,
 			     struct ll_fiemap_info_key *fmkey, int stripeno,