soc/intel/apollolake: Provide interface to update TCC offset

This change provides an interface for apollolake to set TCC before
BIOS reset complete happens in romstage.

With this change, we can add code to update Tcc in devicetree.

BUG=b:117789732
TEST=Match the result from TAT UI

Change-Id: I4419d3bbe2628fcb26ef81828d6325fc952dbabc
Signed-off-by: John Su <john_su@compal.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/29351
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Justin TerAvest <teravest@chromium.org>
Reviewed-by: Sumeet R Pawnikar <sumeet.r.pawnikar@intel.com>

src/soc/intel/apollolake/chip.h

@@ -112,6 +112,9 @@ struct soc_intel_apollolake_config {
 	/* Enable DPTF support */
 	int dptf_enable;
 
+	/* TCC activation offset value in degrees Celsius */
+	int tcc_offset;
+
 	/* PL1 override value in mW for APL */
 	uint16_t tdp_pl1_override_mw;
 	/* PL2 override value in mW for APL */