staging: lustre: fixed sparse warnings related to static declarations

drivers/staging/lustre/lustre/mdc/mdc_request.c:63:5: warning: symbol 'mdc_unpack_capa' was not declared. Should it be static?
drivers/staging/lustre/lustre/mdc/mdc_request.c:150:5: warning: symbol 'mdc_getstatus' was not declared. Should it be static?
drivers/staging/lustre/lustre/mdc/mdc_request.c:217:5: warning: symbol 'mdc_getattr' was not declared. Should it be static?
drivers/staging/lustre/lustre/mdc/mdc_request.c:261:5: warning: symbol 'mdc_getattr_name' was not declared. Should it be static?
drivers/staging/lustre/lustre/mdc/mdc_request.c:444:5: warning: symbol 'mdc_setxattr' was not declared. Should it be static?
drivers/staging/lustre/lustre/mdc/mdc_request.c:455:5: warning: symbol 'mdc_getxattr' was not declared. Should it be static?

Signed-off-by: Janet Liu <jianhua.ljh@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>