KVM: remove long -> void *user -> long cast

kvm_dev_ioctl casts the arg value to void __user *, just to recast it
again to long. This seems unnecessary.

According to objdump the binary code on x86 is unchanged by this patch.
Signed-off-by: NChristian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: NAvi Kivity <avi@qumranet.com>

virt/kvm/kvm_main.c

@@ -1179,7 +1179,6 @@ static int kvm_dev_ioctl_create_vm(void)
 static long kvm_dev_ioctl(struct file *filp,
 			  unsigned int ioctl, unsigned long arg)
 {
-	void __user *argp = (void __user *)arg;
 	long r = -EINVAL;
 
 	switch (ioctl) {
@@ -1196,7 +1195,7 @@ static long kvm_dev_ioctl(struct file *filp,
 		r = kvm_dev_ioctl_create_vm();
 		break;
 	case KVM_CHECK_EXTENSION:
-		r = kvm_dev_ioctl_check_extension((long)argp);
+		r = kvm_dev_ioctl_check_extension(arg);
 		break;
 	case KVM_GET_VCPU_MMAP_SIZE:
 		r = -EINVAL;