util/spd_tools: Add Intel Panther Lake (PTL) platform

This patch add support for PTL platform to the `spd_tools`.
This would be useful to create dynamic SPD for fatcat variants.

BUG=b:347669091
TEST=Able to generate SPD for LP5 DRAM part.

Change-Id: I55c3f49439fb1ad961c6866f03594431e54279b9
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/83822
Reviewed-by: Eric Lai <ericllai@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Ravishankar Sarawadi <ravishankar.sarawadi@intel.com>

spd/lp5/platforms_manifest.generated.txt

@@ -1,6 +1,7 @@
 # Generated by:
 # util/spd_tools/bin/spd_gen spd/lp5/memory_parts.json lp5
 
+PTL,set-0
 MTL,set-0
 ADL,set-0
 PHX,set-1