soc/intel/common: pmclib: add API to get ETR register address

Add a new API to get the ETR register address.

Change-Id: I706f3e220d639a6133625e3cb7267f7009006af2
Signed-off-by: Michael Niewöhner <foss@mniewoehner.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36565
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/common/block/include/intelblocks/pmclib.h

@@ -169,6 +169,9 @@ void pmc_gpe_init(void);
 /* Returns PMC base address */
 uintptr_t soc_read_pmc_base(void);
 
+/* Returns pointer to the ETR register */
+uint32_t *soc_pmc_etr_addr(void);
+
 /*
  * This function returns array of string which represents
  * names for the SMI status register bits. Size of the array is