MIPS: KVM: Remove dead code of TLB index error in kvm_mips_emul_tlbwr()

It's impossible to fall into the error handling of the TLB index after
being masked by (KVM_MIPS_GUEST_TLB_SIZE - 1). Remove the dead code.

Reported-by: James Hogan <[e-mail]>
Signed-off-by: Deng-Cheng Zhu <[e-mail]>
Reviewed-by: James Hogan <[e-mail]>
Signed-off-by: Paolo Bonzini <[e-mail]>

arch/mips/kvm/emulate.c

···
 	get_random_bytes(&index, sizeof(index));
 	index &= (KVM_MIPS_GUEST_TLB_SIZE - 1);
 
-	if (index < 0 || index >= KVM_MIPS_GUEST_TLB_SIZE) {
-		kvm_err("%s: illegal index: %d\n", __func__, index);
-		return EMULATE_FAIL;
-	}
-
 	tlb = &vcpu->arch.guest_tlb[index];
 
 	/*