tools/hv: Use include/uapi with __EXPORTED_HEADERS__

Use the local uapi headers to keep in sync with "recently" added #define's
(e.g. VSS_OP_REGISTER1).

Fixes: 3eb2094c ("Adding makefile for tools/hv")
Cc: <stable@vger.kernel.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>