x86/AMD: limit C1E disable family range

x86/AMD: limit C1E disable family range

Just like for other family values of 0x17 (see "x86/AMD: correct certain
Fam17 checks"), commit 3157bb4e13 ("Add MSR support for various feature
AMD processor families") made the original check for Fam11 here include
families all the way up to Fam17. The involved MSR (0xC0010055),
however, is fully reserved starting from Fam16, and the two bits of
interest are reserved for Fam12 and onwards (albeit I admit I wasn't
able to find any Fam13 doc). Restore the upper bound to be Fam11.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>