remove duplicate line

scripts/toolchain.cmake.in

@@ -2,7 +2,6 @@ set(CMAKE_SYSTEM_NAME Linux)
 set(CMAKE_SYSTEM_PROCESSOR @@TARGET_ARCH@@)
 set(CMAKE_C_COMPILER @@TARGET_CC@@)
 set(CMAKE_CXX_COMPILER @@TARGET_CXX@@)
-set(CMAKE_SYSTEM_NAME Linux)
 set(CMAKE_C_FLAGS "@@TARGET_CFLAGS@@" CACHE STRING "OpenADK CFLAGS" FORCE)
 set(CMAKE_CXX_FLAGS "@@TARGET_CXXFLAGS@@" CACHE STRING "OpenADK CXXFLAGS" FORCE)
 set(CMAKE_INSTALL_SO_NO_EXE 0)