Vlv2TbltDevicePkg/PlatformDxe: Add missing #if

Add missing #if for SENSOR_INFO_VAR_SUPPORT around
the function InitializeSensorInfoVariable().  This
function is referencing 2 global variables that are
not defined, and this breaks VS2017 for undefined
global variables.

Cc: Zailiang Sun <zailiang.sun@intel.com>
Cc: Yi Qian <yi.qian@intel.com>
Cc: Gary Lin <glin@suse.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Zailiang Sun <zailiang.sun@intel.com>
Tested-by: Gary Lin <glin@suse.com>