Kernel: Propagate errors in USBManagement::register_driver()

We currently don't support loadable modules, so all callers of this
function use `MUST()` on the result for now.

Author: spholz

Kernel/Bus/USB/Drivers/HID.cpp

@@ -91,7 +91,7 @@ USB_DEVICE_DRIVER(HIDDriver);
 void HIDDriver::init()
 {
     auto driver = MUST(adopt_nonnull_lock_ref_or_enomem(new (nothrow) HIDDriver()));
-    USBManagement::register_driver(driver);
+    MUST(USBManagement::register_driver(driver));
 }
 
 static constexpr u8 DESCRIPTOR_TYPE_HID = 0x21;

Kernel/Bus/USB/Drivers/MassStorage/MassStorageDriver.cpp

@@ -23,7 +23,7 @@ USB_DEVICE_DRIVER(MassStorageDriver);
 void MassStorageDriver::init()
 {
     auto driver = MUST(adopt_nonnull_lock_ref_or_enomem(new MassStorageDriver()));
-    USBManagement::register_driver(driver);
+    MUST(USBManagement::register_driver(driver));
 }
 
 ErrorOr<void> MassStorageDriver::probe(USB::Device& device)

Kernel/Bus/USB/USBManagement.cpp

@@ -20,10 +20,10 @@ UNMAP_AFTER_INIT USBManagement::USBManagement()
     SysFSUSBBusDirectory::initialize();
 }
 
-void USBManagement::register_driver(NonnullLockRefPtr<Driver> driver)
+ErrorOr<void> USBManagement::register_driver(NonnullLockRefPtr<Driver> driver)
 {
     dbgln_if(USB_DEBUG, "Registering driver {}", driver->name());
-    s_available_drivers->append(driver);
+    return s_available_drivers->try_append(driver);
 }
 
 LockRefPtr<Driver> USBManagement::get_driver_by_name(StringView name)

Kernel/Bus/USB/USBManagement.h

@@ -19,7 +19,7 @@ class USBManagement {
     USBManagement();
     static USBManagement& the();
 
-    static void register_driver(NonnullLockRefPtr<Driver> driver);
+    static ErrorOr<void> register_driver(NonnullLockRefPtr<Driver> driver);
     static LockRefPtr<Driver> get_driver_by_name(StringView name);
     static void unregister_driver(NonnullLockRefPtr<Driver> driver);