[pci] Move PCIe and ACPI code to their own libs

This pulls them out of srv.init (and src/include where the kernel uses
them) and puts them into their own libs for sharing.

src/kernel/kernel.module

@@ -5,7 +5,7 @@ kernel = module("kernel",
     basename = "jsix",
     targets = [ "kernel" ],
     description = "jsix kernel",
-    deps = [ "util", "cpu", "bootproto", "j6" ],
+    deps = [ "util", "cpu", "bootproto", "j6", "acpi" ],
     static = True,
     ld_script = "kernel.ld",
     sources = [