x86/retpoline: Avoid retpolines for built-in __init functions

x86/retpoline: Avoid retpolines for built-in __init functions

[ Upstream commit 66f793099a636862a71c59d4a6ba91387b155e0c ]

There's no point in building init code with retpolines, since it runs before
any potentially hostile userspace does. And before the retpoline is actually
ALTERNATIVEd into place, for much of it.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: karahmed@amazon.de
Cc: peterz@infradead.org
Cc: bp@alien8.de
Link: https://lkml.kernel.org/r/1517484441-1420-2-git-send-email-dwmw@amazon.co.uk
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>