sysfs/cpu: Fix typos in vulnerability documentation

commit 9ecccfaa7cb5249bd31bdceb93fcf5bedb8a24d8 upstream.

Fixes: 87590ce6e ("sysfs/cpu: Add vulnerability folder")
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>