Change in coreboot[master]: soc/intel/common/thermal: Refactor thermal block to improve reusability

[Angel Pons (Code Review)]

Attention is currently required from: Subrata Banik, Maulik V Vaghela, Tim Wawrzynczak, Patrick Rudolph, EricR Lai.
Angel Pons has posted comments on this change. ( https://review.coreboot.org/c/coreboot/+/59509 )

Change subject: soc/intel/common/thermal: Refactor thermal block to improve reusability
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Patch Set 6:

(1 comment)

File src/soc/intel/common/block/thermal/Kconfig:

https://review.coreboot.org/c/coreboot/+/59509/comment/647757fb_c039a37c 
PS4, Line 7: config SOC_INTEL_COMMON_BLOCK_THERMAL_PCI_DEV
           : 	bool
           : 	default n
           : 	select SOC_INTEL_COMMON_BLOCK_THERMAL
           : 	help
           : 	  This option allows to configure PCH thermal registers using Thermal PCI device
           : 	  for chipsets till Ice Lake PCH.
           : 
           : config SOC_INTEL_COMMON_BLOCK_THERMAL_BEHIND_PMC
           : 	bool
           : 	default n
           : 	select SOC_INTEL_COMMON_BLOCK_THERMAL
           : 	help
           : 	  This option allows to configure PCH thermal registers using PMC PWRMBASE
           : 	  for chipsets since Tiger Lake PCH.
> Another way could be […]

Meh, looks like Kconfig doesn't like my idea... I'd simply use a preprocessor check inside `thermal.h`:

#if CONFIG(SOC_INTEL_COMMON_BLOCK_THERMAL_PCI_DEV) &&
     CONFIG(SOC_INTEL_COMMON_BLOCK_THERMAL_BEHIND_PMC)
 #error "<insert error message here>"
 #endif

Or, we could define the `GET_LTT_VALUE` macro independently for each case:

#if CONFIG(SOC_INTEL_COMMON_BLOCK_THERMAL_PCI_DEV)
   /* Trip Point Temp = (LTT / 2 - 50 degree C) */
   #define GET_LTT_VALUE(x) (((x) + 50) * (2))
 #endif
 #if CONFIG(SOC_INTEL_COMMON_BLOCK_THERMAL_BEHIND_PMC)
   /*
    * Trip Point = T2L | T1L | T0L where T2L > T1L > T0L
    * T2L = Bit 28:20
    * T1L = Bit 18:10
    * T0L = Bit 8:0
    */
   #define GET_LTT_VALUE(x) (((x) + 10) << 20 | ((x) + 5) << 10 | (x))
 #endif

This way, there will be a macro redefinition error if both symbols are enabled. If none of them is enabled, something will be undefined.