platform/x86/amd: pmc: Add defines for STB events

Currently `amd-pmc` has two events, but just adds one to the first to
distinguish the second.  Add a clear definition what these events mean.
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20220829162953.5947-3-mario.limonciello@amd.comReviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

drivers/platform/x86/amd/pmc.c

@@ -39,7 +39,8 @@
 #define AMD_PMC_STB_INDEX_ADDRESS	0xF8
 #define AMD_PMC_STB_INDEX_DATA		0xFC
 #define AMD_PMC_STB_PMI_0		0x03E30600
-#define AMD_PMC_STB_PREDEF		0xC6000001
+#define AMD_PMC_STB_S2IDLE_PREPARE	0xC6000001
+#define AMD_PMC_STB_S2IDLE_RESTORE	0xC6000002
 
 /* STB S2D(Spill to DRAM) has different message port offset */
 #define STB_SPILL_TO_DRAM		0xBE
@@ -701,7 +702,7 @@ static void amd_pmc_s2idle_prepare(void)
 	}
 
 	if (enable_stb) {
-		rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF);
+		rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_S2IDLE_PREPARE);
 		if (rc)
 			dev_err(pdev->dev, "error writing to STB: %d\n", rc);
 	}
@@ -724,9 +725,8 @@ static void amd_pmc_s2idle_restore(void)
 	/* Dump the IdleMask to see the blockers */
 	amd_pmc_idlemask_read(pdev, pdev->dev, NULL);
 
-	/* Write data incremented by 1 to distinguish in stb_read */
 	if (enable_stb) {
-		rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF + 1);
+		rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_S2IDLE_RESTORE);
 		if (rc)
 			dev_err(pdev->dev, "error writing to STB: %d\n", rc);
 	}