cpu/x86/lapic: Support x86_64 and clean up code

Most LAPIC registers are 32bit, and thus the use of long is valid on
x86_32, however it doesn't work on x86_64.

* Don't use long as it is 64bit on x86_64, which breaks interrupts
  in QEMU and thus SeaBIOS wouldn't time out the boot menu
* Get rid of unused defines
* Get rid of unused atomic xchg code

Tested on QEMU Q35 with x86_64 enabled: Interrupts work again.
Tested on QEMU Q35 with x86_32 enabled: Interrupts are still working.
Tested on Lenovo T410 with x86_64 enabled.

Change-Id: Iaed1ad956d090625c7bb5cd9cf55cbae16dd82bd
Signed-off-by: Patrick Rudolph <siro@das-labor.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36777
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/soc/amd/common/block/pi/def_callouts.c b/src/soc/amd/common/block/pi/def_callouts.c
index 7126c97..56ce995 100644
--- a/src/soc/amd/common/block/pi/def_callouts.c
+++ b/src/soc/amd/common/block/pi/def_callouts.c
@@ -195,7 +195,7 @@
 	Status = amd_late_run_ap_task(agesadata.ConfigPtr);
 
 	if (Status)
-		printk(BIOS_DEBUG, "There was a problem with %lx returned %s\n",
+		printk(BIOS_DEBUG, "There was a problem with %x returned %s\n",
 			lapicid(), decodeAGESA_STATUS(Status));
 }