KVM: nVMX: Fix bad cleanup on error of get/set nested state IOCTLs

KVM: nVMX: Fix bad cleanup on error of get/set nested state IOCTLs

The handlers of IOCTLs in kvm_arch_vcpu_ioctl() are expected to set
their return value in "r" local var and break out of switch block
when they encounter some error.
This is because vcpu_load() is called before the switch block which
have a proper cleanup of vcpu_put() afterwards.

However, KVM_{GET,SET}_NESTED_STATE IOCTLs handlers just return
immediately on error without performing above mentioned cleanup.

Thus, change these handlers to behave as expected.

Fixes: 8fcc4b5923af ("kvm: nVMX: Introduce KVM_CAP_NESTED_STATE")
Reviewed-by: Mark Kanda <[email protected]>
Reviewed-by: Patrick Colp <[email protected]>
Signed-off-by: Liran Alon <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>