soc/amd/common: Add weak call for platform PCIE slot reset

Since it is fairly uncommon, add a weak call that may be done by
the platform if it has the support.

BUG=b:66690176
BRANCH=none
TEST=coreboot builds.

Change-Id: I50008da6f85039a428184bf9e7642c0aa6610247
Signed-off-by: Marc Jones <marcj303@gmail.com>
Reviewed-on: https://review.coreboot.org/22193
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
diff --git a/src/soc/amd/common/BiosCallOuts.h b/src/soc/amd/common/BiosCallOuts.h
index 1f1ebf7..a2c719f 100644
--- a/src/soc/amd/common/BiosCallOuts.h
+++ b/src/soc/amd/common/BiosCallOuts.h
@@ -64,6 +64,8 @@
 void platform_FchParams_reset(FCH_RESET_DATA_BLOCK *FchParams_reset);
 void platform_FchParams_env(FCH_DATA_BLOCK *FchParams_env);
 void oem_fan_control(FCH_DATA_BLOCK *FchParams);
+AGESA_STATUS platform_PcieSlotResetControl(UINT32 Func, UINTN Data,
+	VOID *ConfigPtr);
 typedef struct {
 	UINT32 CalloutName;
 	CALLOUT_ENTRY CalloutPtr;
diff --git a/src/soc/amd/common/def_callouts.c b/src/soc/amd/common/def_callouts.c
index fd3b5e9..9cea965 100644
--- a/src/soc/amd/common/def_callouts.c
+++ b/src/soc/amd/common/def_callouts.c
@@ -162,13 +162,18 @@
 	return Status;
 }
 
+AGESA_STATUS __attribute__((weak)) platform_PcieSlotResetControl(UINT32 Func,
+	UINTN Data, VOID *ConfigPtr)
+{
+	printk(BIOS_WARNING, "Warning - AGESA callout: %s not supported\n",
+		__func__);
+	return AGESA_UNSUPPORTED;
+}
+
 AGESA_STATUS agesa_PcieSlotResetControl(UINT32 Func, UINTN Data,
 	VOID *ConfigPtr)
 {
-	printk(BIOS_WARNING, "Warning - Missing AGESA callout: %s\n", __func__);
-	AGESA_STATUS Status = AGESA_UNSUPPORTED;
-
-	return Status;
+	return platform_PcieSlotResetControl(Func, Data, ConfigPtr);
 }
 
 AGESA_STATUS agesa_WaitForAllApsFinished(UINT32 Func, UINTN Data,