x86/Intel: also display CPU freq for family 0xf

x86/Intel: also display CPU freq for family 0xf

Actually we can do better than simply bailing for there not being any
PLATFORM_INFO MSR on these. The "max" part of the information is
available in another MSR, alongside the scaling factor (which is
encoded in similar ways to Core/Core2, and hence the decoding table can
be shared).

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Roger Pau Monné <roger.pau@citrix.com>