Add the MEMORY_DEVICE_INFO_KIND_SGX_EPC case, so that enclave
memory is included in the output of "info numa" instead of crashing
the monitor.

Fixes: a7c565a9 ("sgx-epc: Add the fill_device_info() callback support", 2021-09-30)
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>