x86/cpuid: Move featuresets into struct cpuid_policy

x86/cpuid: Move featuresets into struct cpuid_policy

Featuresets will eventually live only once in a struct cpuid_policy, but lots
of code currently uses the global featuresets as a linear bitmap.  Remove the
existing global *_featureset bitmaps, replacing them with *_policy objects
containing named featureset words and a fs[] linear bitmap.

Two new helpers are introduced to scatter/gather a linear featureset bitmap
to/from the fixed word locations in struct cpuid_policy.

The existing calculate_raw_policy() already obtains the scattered raw
featureset.  Gather the raw featureset into raw_policy.fs in
calculate_raw_policy() and drop calculate_raw_featureset() entirely.

Now that host_featureset can't be a straight define of
boot_cpu_data.x86_capability, introduce calculate_host_policy() to suitably
fill in host_policy from boot_cpu_data.x86_capability.  (Future changes will
have additional sanitization logic in this function.)

The PV and HVM policy objects and calculation functions have max introduced to
their names, as there will eventually be a distinction between max and default
policies for each domain type.  The existing logic works in terms of linear
bitmaps, so scatter the result back into the policy objects.

Leave some compatibility defines providing the old *_featureset API.  This
results in no observed change in the *_featureset values, which are still used
at the hypercall and guest_cpuid() interfaces.

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