aocpu: add pre-build for link file. [1/2]

PD#SWPL-140804

Problem:
link file do not support preprocess.

Solution:
add pre-build for link file.

Verify:
N/A

Change-Id: I2db1bdc5533b73843e01b00a1c7c254901190842
Signed-off-by: shijie.xiong <shijie.xiong@amlogic.com>
diff --git a/cmake/root.cmake b/cmake/root.cmake
index 03a3d18..33803b9 100755
--- a/cmake/root.cmake
+++ b/cmake/root.cmake
@@ -135,6 +135,7 @@
         -T"${BOARD_DIR}/lscript.ld"
     )
 elseif(CONFIG_RISCV)
+add_custom_command(TARGET ${TARGET_NAME} PRE_BUILD COMMAND ${CMAKE_C_COMPILER} -I ${BOARD_DIR} -E -xc -P ${BOARD_DIR}/lscript.ld > ${BOARD_DIR}/lscript)
     target_link_libraries(
         ${TARGET_NAME}
         -Wl,--start-group
@@ -142,7 +143,7 @@
         ${COLLECT_LINK_OBJS}
         ${SYSTEM_LIBS} ${COLLECT_LINK_LIBRARIES}
         -Wl,--end-group
-        -T"${BOARD_DIR}/lscript.ld"
+        -T"${BOARD_DIR}/lscript"
     )
 endif()