Add support for Nacon Compact PS4 Wired Controller (0x146b:0x0603)

[annoybot]

Add support for Nacon Compact PS4 Wired Controller (0x146b:0x0603)

Tested and confirmed working on macOS (Apple Silicon) via
SDL_JOYSTICK_HIDAPI_XBOX_360 driver over libusb. All inputs verified:
A/B/X/Y, LB/RB, LT/RT (full analog), both sticks, d-pad, Share/Options.
Center touchpad is inert — XInput protocol has no touchpad data channel.

Problem

This controller uses XInput over a vendor-specific USB interface (no HID).
Platform HID backends (IOHIDManager, hidraw) can't see it — only libusb can.
SDL3 already supports the protocol; two guards blocked the device from reaching
the driver.

Fix

src/hidapi/SDL_hidapi.c — Added 0x146b:0x0603 to SDL_libusb_required[].
The libusb whitelist only had Nintendo devices. Affects macOS and Linux.

src/joystick/hidapi/SDL_hidapi_xbox360.c — Added else if branch in
the macOS MFI guard to let libusb-required devices through instead of deferring
to GCController (which can't see them). Generic — future SDL_libusb_required[]
entries benefit automatically. Not needed on Linux (no MFI guard).

Other Nacon XInput controllers

Only 0x0603 was hardware-tested. Five other Nacon XInput PIDs in
controller_list.h likely need the same fix:

• 0x0601 — BigBen Interactive XBOX 360 Controller
• 0x0604 — NACON Daija Arcade Stick
• 0x0605 — NACON PS4 controller in Xbox mode
• 0x0606 — NACON Unknown Controller
• 0x0609 — NACON Wireless Controller for PS4

Runtime Requirement

Requires libusb (brew install libusb on macOS). SDL3 loads it dynamically
via dlopen("libusb-1.0.dylib").