doc/CMakeLists.txt: Rename CONFIG_DIR to CONF_DIR

Avoids having it look like a Kconfig symbol reference (which gets
detected by an upcoming CI check).

Signed-off-by: Ulf Magnusson <Ulf.Magnusson@nordicsemi.no>
diff --git a/doc/CMakeLists.txt b/doc/CMakeLists.txt
index 6713567..141c36f 100644
--- a/doc/CMakeLists.txt
+++ b/doc/CMakeLists.txt
@@ -191,7 +191,7 @@
 
 set(KI_SCRIPT ${ZEPHYR_BASE}/scripts/filter-known-issues.py)
 set(FIX_TEX_SCRIPT ${ZEPHYR_BASE}/doc/scripts/fix_tex.py)
-set(CONFIG_DIR ${ZEPHYR_BASE}/.known-issues/doc)
+set(CONF_DIR ${ZEPHYR_BASE}/.known-issues/doc)
 
 #
 # HTML section
@@ -225,7 +225,7 @@
   COMMAND ${SPHINX_BUILD_HTML_COMMAND}
   # Merge the Doxygen and Sphinx logs into a single file
   COMMAND ${CMAKE_COMMAND} -P ${ZEPHYR_BASE}/cmake/util/fmerge.cmake ${DOC_LOG} ${DOXY_LOG} ${SPHINX_LOG}
-  COMMAND ${PYTHON_EXECUTABLE} ${KI_SCRIPT} --config-dir ${CONFIG_DIR} --errors ${DOC_WARN} --warnings ${DOC_WARN} ${DOC_LOG}
+  COMMAND ${PYTHON_EXECUTABLE} ${KI_SCRIPT} --config-dir ${CONF_DIR} --errors ${DOC_WARN} --warnings ${DOC_WARN} ${DOC_LOG}
   WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}
   COMMENT "Generating HTML documentation with ${SPHINXBUILD} ${SPHINXOPTS}"
   ${SPHINX_USES_TERMINAL}
@@ -254,7 +254,7 @@
   COMMAND ${SPHINX_BUILD_LATEX_COMMAND}
   # Merge the Doxygen and Sphinx logs into a single file
   COMMAND ${CMAKE_COMMAND} -P ${ZEPHYR_BASE}/cmake/util/fmerge.cmake ${DOC_LOG} ${DOXY_LOG} ${SPHINX_LOG}
-  COMMAND ${PYTHON_EXECUTABLE} ${KI_SCRIPT} --config-dir ${CONFIG_DIR} --errors ${DOC_WARN} --warnings ${DOC_WARN} ${DOC_LOG}
+  COMMAND ${PYTHON_EXECUTABLE} ${KI_SCRIPT} --config-dir ${CONF_DIR} --errors ${DOC_WARN} --warnings ${DOC_WARN} ${DOC_LOG}
   COMMAND ${PYTHON_EXECUTABLE} ${FIX_TEX_SCRIPT} ${SPHINX_OUTPUT_DIR_LATEX}/zephyr.tex
   WORKING_DIRECTORY ${CMAKE_CURRENT_LIST_DIR}
   COMMENT "Generating LaTeX documentation"