soc/xeon_sp: Add weak mainboard_ewl_check for EWL check after FSP-M

EWL (Enhanced Warning Log) is a FSP HOB generated by FSP-M that may
contain several warnings/errors related to core, uncore and memory, etc.

mainboard can override it in its romstage.c for its own
Enhanced Warning Log check.

Change-Id: I6f542e71d20307397c398fd757d9408438f681ed
Signed-off-by: Johnny Lin <johnny_lin@wiwynn.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69143
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Jonathan Zhang <jonzhang@fb.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/soc/intel/xeon_sp/include/soc/romstage.h

@@ -9,4 +9,6 @@
 void mainboard_memory_init_params(FSPM_UPD * mupd);
 void mainboard_rtc_failed(void);
 void save_dimm_info(void);
+void mainboard_ewl_check(void);
+
 #endif /* _SOC_ROMSTAGE_H_ */

src/soc/intel/xeon_sp/romstage.c

@@ -15,6 +15,7 @@ void mainboard_romstage_entry(void)
 
 	fsp_memory_init(false);
 	printk(BIOS_DEBUG, "coreboot fsp_memory_init finished...\n");
+	mainboard_ewl_check();
 
 	unlock_pam_regions();
 
@@ -31,3 +32,4 @@ __weak void mainboard_rtc_failed(void)
 
 }
 __weak void save_dimm_info(void) { }
+__weak void mainboard_ewl_check(void) { }