soc/intel: Move `pmc_clear_pmcon_sts()` into IA common code

This patch moves `pmc_clear_pmcon_sts` function into common code and
remove SoC specific instances.

Accessing PMC GEN_PMCON_A register differs between different Intel
chipsets. Typically, there are two possible ways to perform GEN_PMCON_A
register programming (like `pmc_clear_pmcon_sts()`) as:
1. Using PCI configuration space when GEN_PMCON_A is a PCI configuration
   register.
2. Using MMIO access when GEN_PMCON_A is a memory mapped register.

SoC users to select `SOC_INTEL_MEM_MAPPED_PM_CONFIGURATION` Kconfig to
perform GEN_PMCON_A register programming using PMC MMIO.

BUG=b:211954778
TEST=Able to build brya.

Signed-off-by: Subrata Banik <subratabanik@google.com>
Change-Id: I8d15f421c128630f928a1b6a7e2840056d68d7b1
Reviewed-on: https://review.coreboot.org/c/coreboot/+/62064
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jeff Daly <jeffd@silicom-usa.com>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Reviewed-by: Lean Sheng Tan <sheng.tan@9elements.com>
diff --git a/src/soc/intel/apollolake/Kconfig b/src/soc/intel/apollolake/Kconfig
index 91d203e..9e48971 100644
--- a/src/soc/intel/apollolake/Kconfig
+++ b/src/soc/intel/apollolake/Kconfig
@@ -107,6 +107,7 @@
 	select SOC_INTEL_COMMON_BLOCK_SMBUS
 	select SOC_INTEL_COMMON_FSP_RESET
 	select SOC_INTEL_COMMON_RESET
+	select SOC_INTEL_MEM_MAPPED_PM_CONFIGURATION
 	select SOC_INTEL_NO_BOOTGUARD_MSR
 	select SOUTHBRIDGE_INTEL_COMMON_SMBUS
 	select TSC_MONOTONIC_TIMER