KVM: x86: Clean up CPUID 0x7 sub-leaf loop

Refactor the sub-leaf loop for CPUID 0x7 to move the main leaf out of
said loop.  The emitted code savings is basically a mirage, as the
handling of the main leaf can easily be split to its own helper to avoid
code bloat.

No functional change intended.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/cpuid.c

@@ -573,16 +573,16 @@ static inline int __do_cpuid_func(struct kvm_cpuid_entry2 *entry, u32 function,
 	case 7: {
 		int i;
 
-		for (i = 0; ; ) {
-			do_cpuid_7_mask(&entry[i], i);
-			if (i == entry->eax)
-				break;
+		do_cpuid_7_mask(entry, 0);
+
+		for (i = 1; i <= entry->eax; i++) {
 			if (*nent >= maxnent)
 				goto out;
 
-			++i;
 			do_host_cpuid(&entry[i], function, i);
 			++*nent;
+
+			do_cpuid_7_mask(&entry[i], i);
 		}
 		break;
 	}