mb,sb,soc/intel: Drop useless IO trap handlers

There are four requirements for the SMI to hit a printk()
this commit now removes.

Build must have DEBUG_SMI=y, otherwise any printk() is a no-op
inside SMM.
ASL must have a TRAP() with argument 0x99 or 0x32 for SMIF value.
Platform needs to have IO Trap #3 enabled at IO 0x800.
The SMI monitor must call io_trap_handler for IO Trap #3.

At the moment, only getac/p470 would meet the above criteria
with TRAP(0x32) in its DSDT _INI method. The ASL ignores any
return value of TRAP() calls made.

A mainboard IO trap handler should have precedence over
a southbridge IO trap handler. At the moment we seem to have
no cases of the latter to support, so remove the latter.

Change-Id: I3a3298c8d9814db8464fbf7444c6e0e6ac6ac008
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/70365
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>

src/cpu/x86/smm/smm_module_handler.c

@@ -65,9 +65,6 @@ void io_trap_handler(int smif)
 	 */
 	printk(BIOS_DEBUG, "SMI function trap 0x%x: ", smif);
 
-	if (southbridge_io_trap_handler(smif))
-		return;
-
 	if (mainboard_io_trap_handler(smif))
 		return;