sb/intel/i82801{gx,ix,jx}/acpi/lpc.asl: Drop dead code

This code is not even being build-tested. Drop it before it grows moss.
Also drop a now-unnecessary #undef directive from one mainboard.

Change-Id: I613e77723d108641f16ec732358849c3bc0e49e0
Signed-off-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43220
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Michael Niewöhner
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/getac/p470/dsdt.asl

@@ -1,7 +1,6 @@
 /* SPDX-License-Identifier: GPL-2.0-only */
 
 #define ENABLE_TPM
-#undef  ENABLE_FDC	// There is no Floppy for this laptop
 
 #include <acpi/acpi.h>
 DefinitionBlock(