KVM: TDX: Add macro to retry SEAMCALLs when forcing vCPUs out of guest

KVM: TDX: Add macro to retry SEAMCALLs when forcing vCPUs out of guest

Add a macro to handle kicking vCPUs out of the guest and retrying
SEAMCALLs on TDX_OPERAND_BUSY instead of providing small helpers to be
used by each SEAMCALL.  Wrapping the SEAMCALLs in a macro makes it a
little harder to tease out which SEAMCALL is being made, but
significantly reduces the amount of copy+paste code, and makes it all but
impossible to leave an elevated wait_for_sept_zap.

Reviewed-by: Binbin Wu <binbin.wu@linux.intel.com>
Reviewed-by: Kai Huang <kai.huang@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/20251030200951.3402865-22-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>