x86/microcode/AMD: Extend the container struct

Make it into a container descriptor which is being passed around and
stores important info like the matching container and the patch for the
current CPU. Make it static too.

Later patches will use this and thus get rid of a double container
parsing.

Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/20170120202955.4091-7-bp@alien8.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>