Implement HvFlushVirtualAddress{List,Space}Ex hypercalls in the same way
we've implemented non-EX counterparts.
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
[Initialized valid_bank_mask to silence misguided GCC warnigs. - Radim]
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>