openhcl/tdx: Add support for MCA, MCE, MTRR via tdx/Feature_paravirt_ctls bitmap

[vibhutet]

As per TDX spec, when TDCS.TD_CTRL.REDUCE_VE is set, the guest can control CPU feature paravirtualizaton by writing to the TDCS.FEATURE_PARAVIRT_CTRL. The ohcl-kernel should opt-in to the MCA, MTRR features in the FEATURE_PARVIRT_CTRL to enable guest access to these registers.

[vibhutet]

@cperezvargas can you please add labels for this for tdx

[chris-oo]

I think we actually want #2142 instead of a kernel change, to continue to track upstream