Uninline find_task_by_xxx set of functions

The find_task_by_something is a set of macros are used to find task by pid
depending on what kind of pid is proposed - global or virtual one.  All of
them are wrappers above the most generic one - find_task_by_pid_type_ns() -
and just substitute some args for it.

It turned out, that dereferencing the current->nsproxy->pid_ns construction
and pushing one more argument on the stack inline cause kernel text size to
grow.

This patch moves all this stuff out-of-line into kernel/pid.c.  Together
with the next patch it saves a bit less than 400 bytes from the .text
section.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/kernel/capability.c b/kernel/capability.c
index d4377c5..0d0d886 100644
--- a/kernel/capability.c
+++ b/kernel/capability.c
@@ -63,8 +63,7 @@
 	read_lock(&tasklist_lock);
 
 	if (pid && pid != task_pid_vnr(current)) {
-		target = find_task_by_pid_ns(pid,
-				current->nsproxy->pid_ns);
+		target = find_task_by_vpid(pid);
 		if (!target) {
 			ret = -ESRCH;
 			goto out;
@@ -198,8 +197,7 @@
 	read_lock(&tasklist_lock);
 
 	if (pid > 0 && pid != task_pid_vnr(current)) {
-		target = find_task_by_pid_ns(pid,
-				current->nsproxy->pid_ns);
+		target = find_task_by_vpid(pid);
 		if (!target) {
 			ret = -ESRCH;
 			goto out;