KVM: x86: Drop superfluous check on direct MMU vs. WRITE_PF_TO_SP flag

Remove reexecute_instruction()'s final check on the MMU being direct, as
EMULTYPE_WRITE_PF_TO_SP is only ever set if the MMU is indirect, i.e. is a
shadow MMU.  Prior to commit 93c05d3 ("KVM: x86: improve
reexecute_instruction"), the flag simply didn't exist (and KVM actually
returned "true" unconditionally for both types of MMUs).  I.e. the
explicit check for a direct MMU is simply leftover artifact from old code.

Link: https://lore.kernel.org/r/20240203002343.383056-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

Author: sean-jc

arch/x86/kvm/x86.c

@@ -8806,8 +8806,7 @@ static bool reexecute_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa,
 	 * then zap the SPTE to unprotect the gfn, and then do it all over
 	 * again.  Report the error to userspace.
 	 */
-	return vcpu->arch.mmu->root_role.direct ||
-	       !(emulation_type & EMULTYPE_WRITE_PF_TO_SP);
+	return !(emulation_type & EMULTYPE_WRITE_PF_TO_SP);
 }
 
 static bool retry_instruction(struct x86_emulate_ctxt *ctxt,