mb/google/dedede: Add support for variant specific SMI sleep flow

This support is required to power off certain components that exist only
in certain variants.

BUG=None
TEST=Build and boot Boten to OS.

Change-Id: Ib43ada784666919a4d26246a683dad7f3546fabb
Signed-off-by: Karthikeyan Ramasubramanian <kramasub@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/44587
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Peichao Wang <pwang12@lenovo.corp-partner.google.com>
Reviewed-by: Marco Chen <marcochen@google.com>
Reviewed-by: Furquan Shaikh <furquan@google.com>

src/mainboard/google/dedede/smihandler.c

@@ -21,6 +21,8 @@ void mainboard_smi_sleep(u8 slp_typ)
 	pads = variant_sleep_gpio_table(&num);
 	gpio_configure_pads(pads, num);
 
+	variant_smi_sleep(slp_typ);
+
 	chromeec_smi_sleep(slp_typ, MAINBOARD_EC_S3_WAKE_EVENTS,
 				MAINBOARD_EC_S5_WAKE_EVENTS);
 }
@@ -41,3 +43,7 @@ void mainboard_smi_espi_handler(void)
 {
 	chromeec_smi_process_events();
 }
+
+void __weak variant_smi_sleep(u8 slp_typ)
+{
+}

src/mainboard/google/dedede/variants/baseboard/include/baseboard/variants.h

@@ -36,4 +36,7 @@ int variant_memory_sku(void);
  */
 bool variant_mem_is_half_populated(void);
 
+/* Allow each variants to customize SMI sleep flow. */
+void variant_smi_sleep(u8 slp_typ);
+
 #endif /*__BASEBOARD_VARIANTS_H__ */