KVM: x86 emulator: use correct type for memory address in operands

Currently we use a void pointer for memory addresses.  That's wrong since
these are guest virtual addresses which are not directly dereferencable by
the host.

Use the correct type, unsigned long.
Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/include/asm/kvm_emulate.h

@@ -156,7 +156,10 @@ struct operand {
 		unsigned long orig_val;
 		u64 orig_val64;
 	};
-	unsigned long *ptr;
+	union {
+		unsigned long *reg;
+		unsigned long mem;
+	} addr;
 	union {
 		unsigned long val;
 		u64 val64;