CMakeLists.txt: fix typo SDL_SENSORS_DISABLED -> SDL_SENSOR_DISABLED

CMakeLists.txt

@@ -1578,7 +1578,7 @@ if(NOT HAVE_SDL_FILESYSTEM)
   set(SOURCE_FILES ${SOURCE_FILES} ${FILESYSTEM_SOURCES})
 endif()
 if(NOT HAVE_SDL_SENSORS)
-  set(SDL_SENSORS_DISABLED 1)
+  set(SDL_SENSOR_DISABLED 1)
   file(GLOB SENSORS_SOURCES ${SDL2_SOURCE_DIR}/src/sensor/dummy/*.c)
   set(SOURCE_FILES ${SOURCE_FILES} ${SENSORS_SOURCES})
 endif()