soc/amd/picasso: Use PSP Sx command only for S3

Skip sending MboxBiosCmdSxInfo for sleep states other than S3.  The
PSP only acts on S3 and ignores all others.  As a result, the command
register is not cleared upon return and coreboot reports a timeout.

BUG=b:153622879
TEST=Use halt from command line, verify command skipped.

Signed-off-by: Marshall Dawson <marshalldawson3rd@gmail.com>
Change-Id: Ic47b8507e29e4c53898e88fb46e532b71df87d07
Reviewed-on: https://review.coreboot.org/c/coreboot/+/43038
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>

src/soc/amd/picasso/smihandler.c

@@ -208,7 +208,8 @@ static void sb_slp_typ_handler(void)
 						reg32);
 		} /* if (CONFIG(ELOG_GSMI)) */
 
-		psp_notify_sx_info(slp_typ);
+		if (slp_typ == ACPI_S3)
+			psp_notify_sx_info(ACPI_S3);
 
 		smu_sx_entry(); /* Leave SlpTypeEn clear, SMU will set */
 		printk(BIOS_ERR, "Error: System did not go to sleep\n");