soc/intel/elkhartlake: Fix EHL mainboard build fail errors

When EHL initial mainboard patch is uploaded, there are some build
errors caused by EHL soc codes. Here are the fixes:
1. include gpio_op.asl to resolve undefined variables in scs.asl
2. remove unused variables in fsp_params.c
3. rearrage sequences of #includes to fix build dependency of
   soc/gpio_defs.h in intelblocks/gpio.h
4. add the __weak to mainboard_memory_init_params function
5. add the missing _len as per this patch changes
   https://review.coreboot.org/c/coreboot/+/45873

Signed-off-by: Tan, Lean Sheng <lean.sheng.tan@intel.com>
Change-Id: Idaa8b0b5301742287665abde065ad72965bc62b3
Reviewed-on: https://review.coreboot.org/c/coreboot/+/47804
Reviewed-by: Werner Zeh <werner.zeh@siemens.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/elkhartlake/acpi/gpio.asl

@@ -3,6 +3,7 @@
 #include <intelblocks/gpio.h>
 #include <soc/gpio_defs.h>
 #include <soc/intel/common/acpi/gpio.asl>
+#include <soc/intel/common/block/acpi/acpi/gpio_op.asl>
 #include <soc/irq.h>
 #include <soc/pcr_ids.h>
 

src/soc/intel/elkhartlake/fsp_params.c

@@ -44,17 +44,13 @@ static const pci_devfn_t serial_io_dev[] = {
 
 static void parse_devicetree(FSP_S_CONFIG *params)
 {
-	const struct soc_intel_elkhartlake_config *config = config_of_soc();
 	/* TODO: Update with UPD override as FSP matures */
 }
 
 /* UPD parameters to be initialized before SiliconInit */
 void platform_fsp_silicon_init_params_cb(FSPS_UPD *supd)
 {
-	unsigned int i;
-	struct device *dev;
 	FSP_S_CONFIG *params = &supd->FspsConfig;
-	struct soc_intel_elkhartlake_config *config = config_of_soc();
 
 	/* Parse device tree and fill in FSP UPDs */
 	parse_devicetree(params);

src/soc/intel/elkhartlake/include/soc/gpio.h

@@ -3,8 +3,8 @@
 #ifndef _SOC_ELKHARTLAKE_GPIO_H_
 #define _SOC_ELKHARTLAKE_GPIO_H_
 
-#include <intelblocks/gpio.h>
 #include <soc/gpio_defs.h>
+#include <intelblocks/gpio.h>
 
 #define CROS_GPIO_NAME		"INT34C8"
 #define CROS_GPIO_COMM0_NAME    "INT34C8:00"

src/soc/intel/elkhartlake/romstage/fsp_params.c

@@ -25,7 +25,7 @@ void platform_fsp_memory_init_params_cb(FSPM_UPD *mupd, uint32_t version)
 	mainboard_memory_init_params(mupd);
 }
 
-void mainboard_memory_init_params(FSPM_UPD *mupd)
+__weak void mainboard_memory_init_params(FSPM_UPD *mupd)
 {
 	/* TODO: Update later together with UPD updates */
 }

src/soc/intel/elkhartlake/romstage/romstage.c

@@ -62,7 +62,7 @@ static void save_dimm_info(void)
 	/* Allow mainboard to override DRAM part number. */
 	dram_part_num = mainboard_get_dram_part_num();
 	if (dram_part_num) {
-		dram_part_num = strlen(dram_part_num);
+		dram_part_num_len = strlen(dram_part_num);
 		is_dram_part_overridden = true;
 	}