The check to free the Hyper-V control table header was reversed. This
fixes it.

Fixes: 81b18bce ("Drivers: HV: Send one page worth of kmsg dump over Hyper-V during panic")
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>