arm/arm64: KVM: Fix ioctl error handling

arm/arm64: KVM: Fix ioctl error handling

Calling return copy_to_user(...) in an ioctl will not
do the right thing if there's a pagefault:
copy_to_user returns the number of bytes not copied
in this case.

Fix up kvm to do
	return copy_to_user(...)) ?  -EFAULT : 0;

everywhere.

Cc: [email protected]
Acked-by: Christoffer Dall <[email protected]>
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>