KVM: TDX: Convert INIT_MEM_REGION and INIT_VCPU to "unlocked" vCPU ioctl

KVM: TDX: Convert INIT_MEM_REGION and INIT_VCPU to "unlocked" vCPU ioctl

Handle the KVM_TDX_INIT_MEM_REGION and KVM_TDX_INIT_VCPU vCPU sub-ioctls
in the unlocked variant, i.e. outside of vcpu->mutex, in anticipation of
taking kvm->lock along with all other vCPU mutexes, at which point the
sub-ioctls _must_ start without vcpu->mutex held.

No functional change intended.

Reviewed-by: Kai Huang <kai.huang@intel.com>
Co-developed-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Kai Huang <kai.huang@intel.com>
Link: https://patch.msgid.link/20251030200951.3402865-24-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>