docs: remove invalid arg in confgen invocation on docs generation

docs/conf_common.py

@@ -97,7 +97,6 @@ confgen_args = [sys.executable,
                 "../../tools/kconfig_new/confgen.py",
                 "--kconfig", "../../Kconfig",
                 "--config", temp_sdkconfig_path,
-                "--create-config-if-missing",
                 "--env", "COMPONENT_KCONFIGS={}".format(" ".join(kconfigs)),
                 "--env", "COMPONENT_KCONFIGS_PROJBUILD={}".format(" ".join(kconfig_projbuilds)),
                 "--env", "IDF_PATH={}".format(idf_path),