boot-qemu.py: Handle LoongArch's EFI firmware location change

Loongson renamed this file in [1], which results in a 404 file getting
downloaded as the firmware, so QEMU obviously refuses to start. If the
old firmware file does not exist locally already, download and use the
new file name.

Link: loongson/Firmware@638906d [1]
Signed-off-by: Nathan Chancellor <[email protected]>

Author: nathanchance

boot-qemu.py

@@ -511,6 +511,10 @@ def __init__(self):
         bios = Path(utils.BOOT_UTILS, 'images', self._initrd_arch,
                     'edk2-loongarch64-code.fd')
         if not bios.exists():
+            # Loongson renamed this in https://github.com/loongson/Firmware/commit/638906de6143283d86c70d80f4e9a30b50731c24
+            # so download it to the new location if it does not exist already.
+            bios = bios.with_name('QEMU_EFI.fd')
+
             bios.parent.mkdir(exist_ok=True, parents=True)
             firmware_url = f"https://github.com/loongson/Firmware/raw/main/LoongArchVirtMachine/{bios.name}"
             utils.green(