selftests/nolibc: use EFI -bios for LoongArch qemu

qemu for LoongArch does not work properly with direct kernel boot.
The kernel will panic during initialization and hang without any output.

When booting in EFI mode everything work correctly.

While users most likely don't have the LoongArch EFI binary installed at
least an explicit error about 'file not found' is better than a hanging
test without output that can never succeed.

Link: https://lore.kernel.org/loongarch/1738d60a-df3a-4102-b1da-d16a29b6e06a@t-8ch.de/Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Willy Tarreau <w@1wt.eu>
Link: https://lore.kernel.org/r/20231031-nolibc-out-of-tree-v1-1-47c92f73590a@weissschuh.net

tools/testing/selftests/nolibc/Makefile

@@ -88,6 +88,13 @@ QEMU_ARCH_s390       = s390x
 QEMU_ARCH_loongarch  = loongarch64
 QEMU_ARCH            = $(QEMU_ARCH_$(XARCH))
 
+QEMU_BIOS_DIR = /usr/share/edk2/
+QEMU_BIOS_loongarch = $(QEMU_BIOS_DIR)/loongarch64/OVMF_CODE.fd
+
+ifneq ($(QEMU_BIOS_$(XARCH)),)
+QEMU_ARGS_BIOS = -bios $(QEMU_BIOS_$(XARCH))
+endif
+
 # QEMU_ARGS : some arch-specific args to pass to qemu
 QEMU_ARGS_i386       = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_x86_64     = -M pc -append "console=ttyS0,9600 i8042.noaux panic=-1 $(TEST:%=NOLIBC_TEST=%)"
@@ -101,7 +108,7 @@ QEMU_ARGS_ppc64le    = -M powernv -append "console=hvc0 panic=-1 $(TEST:%=NOLIBC
 QEMU_ARGS_riscv      = -M virt -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_s390       = -M s390-ccw-virtio -m 1G -append "console=ttyS0 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
 QEMU_ARGS_loongarch  = -M virt -append "console=ttyS0,115200 panic=-1 $(TEST:%=NOLIBC_TEST=%)"
-QEMU_ARGS            = $(QEMU_ARGS_$(XARCH)) $(QEMU_ARGS_EXTRA)
+QEMU_ARGS            = $(QEMU_ARGS_$(XARCH)) $(QEMU_ARGS_BIOS) $(QEMU_ARGS_EXTRA)
 
 # OUTPUT is only set when run from the main makefile, otherwise
 # it defaults to this nolibc directory.