x86/cpu: Move set_cpumask() calls into c_early_init()

x86/cpu: Move set_cpumask() calls into c_early_init()

Before c/s 44e24f8567 "x86: don't call generic_identify() redundantly", the
commandline-provided masks would take effect in Xen's view of the processor
features.

As the masks got applied after the query for features, the redundant call to
generic_identify() would clobber the pre-masking feature information with the
post-masking information.

Move the set_cpumask() calls into c_early_init() so the effects of the command
line parameters take place before the main query for features in
generic_identify().

The cpuid_mask_* command line parameters now limit the entire system.
Subsequent changes will cause the mask MSRs to be context switched per-domain,
removing the need to use the command line parameters for heterogeneous
levelling purposes.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>