docs: vfio: fix header path

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=2188088

commit d7ba365
Author: Jiri Pirko <jiri@nvidia.com>
Date:   Fri Mar 10 10:58:57 2023 +0100

    docs: vfio: fix header path

    The text points to a different header file, fix by changing
    the path to "uapi".

    Signed-off-by: Jiri Pirko <jiri@nvidia.com>
    Reviewed-by: Yi Liu <yi.l.liu@intel.com>
    Link: https://lore.kernel.org/r/20230310095857.985814-1-jiri@resnulli.us
    Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Author: Alex Williamson

Documentation/driver-api/vfio.rst

@@ -242,7 +242,7 @@ group and can access them as follows::
 VFIO User API
 -------------------------------------------------------------------------------
 
-Please see include/linux/vfio.h for complete API documentation.
+Please see include/uapi/linux/vfio.h for complete API documentation.
 
 VFIO bus driver API
 -------------------------------------------------------------------------------