KVM: x86: Fold 'enum kvm_ex_reg' definitions into 'enum kvm_reg'

Now that indexing into arch.regs is either protected by WARN_ON_ONCE or
done with hardcoded enums, combine all definitions for registers that
are tracked by regs_avail and regs_dirty into 'enum kvm_reg'.  Having a
single enum type will simplify additional cleanup related to regs_avail
and regs_dirty.
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -156,10 +156,8 @@ enum kvm_reg {
 	VCPU_REGS_R15 = __VCPU_REGS_R15,
 #endif
 	VCPU_REGS_RIP,
-	NR_VCPU_REGS
-};
+	NR_VCPU_REGS,
 
-enum kvm_reg_ex {
 	VCPU_EXREG_PDPTR = NR_VCPU_REGS,
 	VCPU_EXREG_CR3,
 	VCPU_EXREG_RFLAGS,

arch/x86/kvm/kvm_cache_regs.h

@@ -85,7 +85,7 @@ static inline u64 kvm_pdptr_read(struct kvm_vcpu *vcpu, int index)
 
 	if (!test_bit(VCPU_EXREG_PDPTR,
 		      (unsigned long *)&vcpu->arch.regs_avail))
-		kvm_x86_ops->cache_reg(vcpu, (enum kvm_reg)VCPU_EXREG_PDPTR);
+		kvm_x86_ops->cache_reg(vcpu, VCPU_EXREG_PDPTR);
 
 	return vcpu->arch.walk_mmu->pdptrs[index];
 }