Tools: Testbench: Remove -Wl,-EL to avoid build fail with xt-clang

The linker option to indicate little endian is unused and the
warning causes build fail:

clang-10clang-10: : errorerror: : -Wl,-EL: 'linker' input unused
[-Werror,-Wunused-command-line-argument]-Wl,-EL: 'linker' input unused
[-Werror,-Wunused-command-line-argument]

clang-10: error: -Wl,-EL: 'linker' input unused
[-Werror,-Wunused-command-line-argument]
clang-10: error: -Wl,-EL: 'linker' input unused
[-Werror,-Wunused-command-line-argument]
gmake[2]: *** [CMakeFiles/testbench.dir/build.make:76:
CMakeFiles/testbench.dir/testbench.c.o] Error 1

Signed-off-by: Seppo Ingalsuo <seppo.ingalsuo@linux.intel.com>

tools/testbench/CMakeLists.txt

@@ -41,7 +41,7 @@ if (supports_implicit_fallthrough)
     set(implicit_fallthrough -Wimplicit-fallthrough)
 endif()
 
-target_compile_options(testbench PRIVATE -g -O3 -Wall -Werror -Wl,-EL -Wmissing-prototypes
+target_compile_options(testbench PRIVATE -g -O3 -Wall -Werror -Wmissing-prototypes
   ${implicit_fallthrough} -DCONFIG_LIBRARY -DCONFIG_LIBRARY_STATIC -imacros${config_h})
 
 target_link_libraries(testbench PRIVATE -lm)