Staging: lustre: Mark internal functions as static

This patch makes functions mgc_logname2resid, mgc_set_info_async
and mgc_init static as these are only used internally.

This also eliminates sparse warnings of the type:
warning: symbol * was not declared. Should it be static?

Signed-off-by: Darshana Padmadas <darshanapadmadas@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>