soc/intel/meteorlake: Implement `soc_is_ish_partition_enabled` override

This patch implements `soc_is_ish_partition_enabled()` override to
uniquely identify the SKU type between ISH and non-ISH to conclude
if ISH partition is enabled and need to retrieve the ISH version from
CSE FPT by sending a HECI command.

BUG=b:285405031   
TEST=Able to uniquely identify the ISH SKUs while booting
    to google/rex_ec_ish to dump the ISH version.

Change-Id: I48358ad9e2e582e8b2274cbf4655de01f8792e6c
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/77177
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Dinesh Gehlot <digehlot@google.com>
Reviewed-by: Kapil Porwal <kapilporwal@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/meteorlake/chip.c

@@ -122,6 +122,20 @@ const char *soc_acpi_name(const struct device *dev)
 }
 #endif
 
+#if CONFIG(SOC_INTEL_STORE_ISH_FW_VERSION)
+/* SoC override API to identify if ISH Firmware existed inside CSE FPT */
+bool soc_is_ish_partition_enabled(void)
+{
+	struct device *ish = pcidev_path_on_root(PCI_DEVFN_ISH);
+	uint16_t ish_pci_id = ish ? pci_read_config16(ish, PCI_DEVICE_ID) : 0xFFFF;
+
+	if (ish_pci_id == 0xFFFF)
+		return false;
+
+	return true;
+}
+#endif
+
 /* SoC routine to fill GPIO PM mask and value for GPIO_MISCCFG register */
 static void soc_fill_gpio_pm_configuration(void)
 {