Move pir table offset from ebda to a global variable.

Also, make sure the pir table is defined with the 16bit code.
diff --git a/Makefile b/Makefile
index 8faa1f4..24c67c2 100644
--- a/Makefile
+++ b/Makefile
@@ -10,11 +10,10 @@
 # Source files
 SRCBOTH=output.c util.c floppy.c ata.c system.c mouse.c kbd.c pci.c \
         serial.c clock.c pic.c cdrom.c ps2port.c smpdetect.c resume.c \
-        pnpbios.c
+        pnpbios.c pirtable.c
 SRC16=$(SRCBOTH) disk.c apm.c pcibios.c vgahooks.c
 SRC32=$(SRCBOTH) post.c shadow.c post_menu.c memmap.c coreboot.c boot.c \
-      acpi.c pirtable.c smm.c mptable.c smbios.c pciinit.c \
-      optionroms.c
+      acpi.c smm.c mptable.c smbios.c pciinit.c optionroms.c
 TABLESRC=font.c cbt.c floppy_dbt.c
 cc-option = $(shell if test -z "`$(1) $(2) -S -o /dev/null -xc \