x86: Refactor PIRQ routing support

PIRQ routing is pretty much common in Intel chipset. It has several
PIRQ links (normally 8) and corresponding registers (either in PCI
configuration space or memory-mapped IBASE) to configure the legacy
8259 IRQ vector mapping. Refactor current Queensbay PIRQ routing
support using device tree and move it to a common place, so that we
can easily add PIRQ routing support on a new platform.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
diff --git a/lib/fdtdec.c b/lib/fdtdec.c
index b586da2..1808350 100644
--- a/lib/fdtdec.c
+++ b/lib/fdtdec.c
@@ -77,6 +77,7 @@
 	COMPAT(INTEL_QRK_MRC, "intel,quark-mrc"),
 	COMPAT(SOCIONEXT_XHCI, "socionext,uniphier-xhci"),
 	COMPAT(COMPAT_INTEL_PCH, "intel,bd82x6x"),
+	COMPAT(COMPAT_INTEL_IRQ_ROUTER, "intel,irq-router"),
 };
 
 const char *fdtdec_get_compatible(enum fdt_compat_id id)