qemu: Update to 8.0.0

* Add libusb1 dependency unconditionally.
* Add graphics/SDL2_image for sdl option.

Changelog:
8.0.0
Highlights include:

  * ARM: emulation support for FEAT_EVT, FEAT_FGT, and AArch32 ARMv8-R
  * ARM: CPU emulation for Cortex-A55 and Cortex-R52, and new Olimex STM32 H405
    machine type
  * ARM: gdbstub support for M-profile system registers
  * HPPA: fid (Floating-Point Identify) instruction support and 32-bit
    emulation improvements
  * RISC-V: additional ISA and Extension support for smstateen, native debug
    icount trigger, cache-related PMU events in virtual mode, Zawrs/Svadu/
    T-Head/Zicond extensions, and ACPI support
  * RISC-V: updated machine support for OpenTitan, PolarFire, and OpenSBI
  * RISC-V: wide ranges of fixes covering PMP propagation for TLB, mret
    exceptions, uncompressed instructions, and other emulation/virtualization
    improvements
  * s390x: improved zPCI passthrough device handling
  * s390x: support for asynchronous teardown of memory of secure KVM guests
    during reboot
  * x86: support for Xen guests under KVM with Linux v5.12+
  * x86: new SapphireRapids CPU model
  * x86: TCG support for FSRM, FZRM, FSRS, and FSRC CPUID flags
  * virtio-mem: support for using preallocation in conjunction with live
    migration
  * VFIO: experimental migration support updated to v2 VFIO migration protocol
  * qemu-nbd: improved efficient over TCP and when using TLS
  * and lots more...

(ryoon)