of: Skip devicetree kunit tests when RISCV+ACPI doesn't populate root node

of: Skip devicetree kunit tests when RISCV+ACPI doesn't populate root node

Starting with commit 69a8b62a7aa1 ("riscv: acpi: avoid errors caused by
probing DT devices when ACPI is used"), riscv images no longer populate
devicetree if ACPI is enabled. This causes unit tests to fail which require
the root node to be set.

  # Subtest: of_dtb
  # module: of_test
  1..2
  # of_dtb_root_node_found_by_path: EXPECTATION FAILED at drivers/of/of_test.c:21
  Expected np is not null, but is
  # of_dtb_root_node_found_by_path: pass:0 fail:1 skip:0 total:1
  not ok 1 of_dtb_root_node_found_by_path
  # of_dtb_root_node_populates_of_root: EXPECTATION FAILED at drivers/of/of_test.c:31
  Expected of_root is not null, but is
  # of_dtb_root_node_populates_of_root: pass:0 fail:1 skip:0 total:1
  not ok 2 of_dtb_root_node_populates_of_root

Skip those tests for RISCV if the root node is not populated.

Fixes: 69a8b62a7aa1 ("riscv: acpi: avoid errors caused by probing DT devices when ACPI is used")
Cc: Han Gao <rabenda.cn@gmail.com>
Cc: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Paul Walmsley <pjw@kernel.org>  # arch/riscv
Link: https://patch.msgid.link/20251023160415.705294-1-linux@roeck-us.net
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>