audit: fix incorrect type of sessionid

The type of task->sessionid is unsigned int, the return
type of audit_get_sessionid should be consistent with it.
Signed-off-by: Gao feng <gaofeng@cn.fujitsu.com>
Signed-off-by: Richard Guy Briggs <rgb@redhat.com>
Signed-off-by: Eric Paris <eparis@redhat.com>

include/linux/audit.h

@@ -202,7 +202,7 @@ static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
 	return tsk->loginuid;
 }
 
-static inline int audit_get_sessionid(struct task_struct *tsk)
+static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
 {
 	return tsk->sessionid;
 }
@@ -359,7 +359,7 @@ static inline kuid_t audit_get_loginuid(struct task_struct *tsk)
 {
 	return INVALID_UID;
 }
-static inline int audit_get_sessionid(struct task_struct *tsk)
+static inline unsigned int audit_get_sessionid(struct task_struct *tsk)
 {
 	return -1;
 }