examples/elf: fix cmake build error

CMake Error at cmake/nuttx_parse_function_args.cmake:76 (message):
  : unparsed INCLUDES;/home/neo/projects/nuttx/apps/examples/elf
Call Stack (most recent call first):
  cmake/nuttx_add_application.cmake:77 (nuttx_parse_function_args)
  /home/neo/projects/nuttx/apps/examples/elf/CMakeLists.txt:24 (nuttx_add_application)

Signed-off-by: xuxingliang <[email protected]>

Author: XuNeo

examples/elf/CMakeLists.txt

@@ -21,8 +21,7 @@
 # ##############################################################################
 
 if(CONFIG_EXAMPLES_ELF)
-  nuttx_add_application(NAME elf INCLUDES ${CMAKE_CURRENT_SOURCE_DIR} SRCS
-                        elf_main.c)
+  nuttx_add_application(NAME elf SRCS elf_main.c)
 
   # TODO: tests