soc/intel/meteorlake: Introduce different SoC flavors of Meteor Lake

This patch introduces the different SoC flavors of Intel Meteor Lake as:
* MTL-U
* MTL-P
* MTL-S

MTL-U and MTL-P are PCH less designs, while MTL-S is with PCH die.
The task for mainboard is to specify the correct SoC type rather than
selecting the MTL SoC by default.

This change is necessary to support the different SoC flavors of Intel
Meteor Lake.

BUG=b:276697173
TEST=Able to build and boot google/rex.

Change-Id: I27404bbbd0b489412953118e140f6f39b6e43426
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/75606
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Reviewed-by: Tarun Tuli <taruntuli@google.com>

src/soc/intel/meteorlake/Kconfig

@@ -1,7 +1,23 @@
 config SOC_INTEL_METEORLAKE
 	bool
 	help
-	  Intel Meteorlake support
+	  Intel Meteorlake support. Mainboards should specify the SoC
+	  type using the `SOC_INTEL_METEORLAKE_*` options instead
+	  of selecting this option directly.
+
+config SOC_INTEL_METEORLAKE_U_P
+	bool
+	select SOC_INTEL_METEORLAKE
+	help
+	  Choose this option if your mainboard has a MTL-U (15W) or MTL-P (28W) SoC.
+	  Note, MTL-U/P SoC combines Compute, GFX, SoC and IOE die.
+
+config SOC_INTEL_METEORLAKE_S
+	bool
+	select SOC_INTEL_METEORLAKE
+	help
+	  Choose this option if your mainboard has a MTL-S (45W) SoC.
+	  Note, MTL-S SoC combines Compute, GFX, SoC, IOE and PCH die.
 
 if SOC_INTEL_METEORLAKE