Kernel/SysFS: Add PCI exposed folder

Author: https://github.com/supercomputer7
Commit: 1baa05d6b2
Pull-request: https://github.com/SerenityOS/serenity/pull/7509
Reviewed-by: https://github.com/BertalanD
Reviewed-by: https://github.com/awesomekling

Kernel/PCI/Initializer.cpp

@@ -51,6 +51,8 @@ UNMAP_AFTER_INIT void initialize()
         VERIFY_NOT_REACHED();
     }
 
+    PCI::BusExposedFolder::initialize();
+
     PCI::enumerate([&](const Address& address, ID id) {
         dmesgln("{} {}", address, id);
     });