[ACPI] acpi_register_gsi() fix needed for ACPICA 20051021

Use the #define for ACPI_LEVEL_SENSITIVE instead of assuming
non-zero, because ACPICA 20051021 changes its value to zero.

Also, use uniform variable names:
edge_level -> triggering
active_high_low -> polarity

Signed-off-by: Len Brown <len.brown@intel.com>
diff --git a/arch/x86_64/kernel/mpparse.c b/arch/x86_64/kernel/mpparse.c
index ba817e7..dc49bfb 100644
--- a/arch/x86_64/kernel/mpparse.c
+++ b/arch/x86_64/kernel/mpparse.c
@@ -964,7 +964,7 @@
 
 	mp_ioapic_routing[ioapic].pin_programmed[idx] |= (1<<bit);
 
-	if (triggering) {
+	if (triggering == ACPI_LEVEL_SENSITIVE) {
 		/*
 		 * For PCI devices assign IRQs in order, avoiding gaps
 		 * due to unused I/O APIC pins.