Fix the following error from gcc:
Vlv2TbltDevicePkg/Wpce791/LpcDriver.c: In function ?LpcDriverStart?:
Vlv2TbltDevicePkg/Wpce791/LpcDriver.c:239:27: error: variable ?LpcDev? set but not used [-Werror=unused-but-set-variable]
Cc: David Wei <david.wei@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Gary Lin <glin@suse.com>