[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/kernel/kernel.module

@@ -43,7 +43,6 @@ kernel = module("kernel",
         "objects/vm_area.cpp",
         "page_table.cpp",
         "page_tree.cpp",
-        "pci.cpp",
         "scheduler.cpp",
         "smp.cpp",
         "smp.s",