Revert "x86/hyper-v: include hyperv/ only when CONFIG_HYPERV is set"

This reverts commit 2e252fbf as it is
obviously not correct.

And it should have gone in through the x86 tree :(

Reported-by: Colin King <colin.king@canonical.com>
Reported-by: Ingo Molnar <mingo@kernel.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Andy Shevchenko <andy.shevchenko@gmail.com>
Cc: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>