tests/vm: fix interactive boot

For reasons still not clear to me passing the single dashed
-interactive would confuse the argument parsing enough we tried to
pass "nterative" as a string to the launch command causing failure and
head scratching.

Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
Message-ID: <20260226185303.1920021-6-alex.bennee@linaro.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

tests/vm/Makefile.include

@@ -154,6 +154,6 @@ vm-boot-ssh-%: $(IMAGES_DIR)/%.img $(VM_VENV)
 		$(if $(EFI_AARCH64),--efi-aarch64 $(EFI_AARCH64)) \
 		$(if $(LOG_CONSOLE),--log-console) \
 		--image "$<" \
-		$(if $(ROOT_USER),--interactive-root,-interactive) \
+		$(if $(ROOT_USER),--interactive-root,--interactive) \
 		false, \
 		"  VM-BOOT-SSH $*") || true