[Zion][Denali] Move to MSI for AHCI devices.

This will allow us to properly do interrupts for XHCI devices in the
future.

Also move PCI device header parsing to a shared library.

Get rid of the old irq register format which supplied an irq number and
instead pass the appropriate irq number back out to the caller.

zion/syscall/syscall.cpp

@@ -77,7 +77,7 @@ extern "C" z_err_t SyscallHandler(uint64_t call_id, void* req) {
     CASE(PortSend);
     CASE(PortRecv);
     CASE(PortPoll);
-    CASE(IrqRegister);
+    CASE(MsiIrqRegister);
     CASE(EndpointCreate);
     CASE(EndpointSend);
     CASE(EndpointRecv);