sb/intel/i82801gx/lpc.c: Use post_code()

Use post_code() instead of 'outb(value, CONFIG_POST_IO_PORT)'.

Change-Id: I1ba6bff810b61a1249cda6e96eb40f4a81381322
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69901
Reviewed-by: Felix Held <felix-coreboot@felixheld.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

src/southbridge/intel/i82801gx/lpc.c

@@ -445,7 +445,7 @@ static void lpc_final(struct device *dev)
 	outw(tco1_cnt, DEFAULT_PMBASE + 0x60 + TCO1_CNT);
 
 	/* Indicate finalize step with post code */
-	outb(POST_OS_BOOT, 0x80);
+	post_code(POST_OS_BOOT);
 }
 
 static const char *lpc_acpi_name(const struct device *dev)