platform/x86: amd-pmc: Only report STB errors when STB enabled

Currently if STB is disabled but an earlier function reported an
error an incorrect error will be emitted about failing to write to
STB.

Correct this logic error by only showing errors when STB is enabled.
Suggested-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mario Limonciello <mario.limonciello@amd.com>
Link: https://lore.kernel.org/r/20220317190301.6818-1-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

@@ -655,10 +655,11 @@ static void amd_pmc_s2idle_prepare(void)
 		return;
 	}
 
-	if (enable_stb)
+	if (enable_stb) {
 		rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF);
 		if (rc)
 			dev_err(pdev->dev, "error writing to STB: %d\n", rc);
+	}
 }
 
 static void amd_pmc_s2idle_restore(void)
@@ -679,10 +680,11 @@ static void amd_pmc_s2idle_restore(void)
 	amd_pmc_idlemask_read(pdev, pdev->dev, NULL);
 
 	/* Write data incremented by 1 to distinguish in stb_read */
-	if (enable_stb)
+	if (enable_stb) {
 		rc = amd_pmc_write_stb(pdev, AMD_PMC_STB_PREDEF + 1);
 		if (rc)
 			dev_err(pdev->dev, "error writing to STB: %d\n", rc);
+	}
 
 	/* Notify on failed entry */
 	amd_pmc_validate_deepest(pdev);