[init] Move PCIe probing to srv.init

This was kept in the kernel as a way to keep exercising the code, but it
doesn't belong there. This moves it to init, which doesn't do anything
but probe for devices currently - but at least it's executing the code
in userspace now.

src/libraries/bootproto/bootproto.module

@@ -3,6 +3,7 @@
 bp = module("bootproto",
     kind = "lib",
     public_headers = [
+        "bootproto/acpi.h",
         "bootproto/bootconfig.h",
         "bootproto/devices/framebuffer.h",
         "bootproto/init.h",

src/libraries/bootproto/bootproto/acpi.h

@@ -0,0 +1,15 @@
+#pragma once
+/// \file bootproto/acpi.h
+/// Data structures for passing ACPI tables to the init server
+
+#include <util/counted.h>
+
+namespace bootproto {
+
+struct acpi
+{
+    util::const_buffer region;
+    void const *root;
+};
+
+} // namespace bootproto

src/libraries/bootproto/bootproto/init.h

@@ -10,7 +10,7 @@
 
 namespace bootproto {
 
-enum class module_type : uint8_t { none, initrd, device, };
+enum class module_type : uint8_t { none, initrd, device, acpi };
 
 struct module
 {