staging:lustre:lnet:selftest: fix sparse warnings

Fix sparse warnings: symbol X was not declared. Should it be static?
Some functions used only in files where they are declared. They can
be static.

Signed-off-by: Anton Saraev <antonysaraev@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>