Don't pass -m32 to libcc1 on arm-linux
    
    When I run gdb.compile/ tests on arm-linux, I get the following fails,
    
    (gdb) compile code -- ;^M
    arm-none-linux-gnueabihf-gcc: error: unrecognized command line option '-m32'; did you mean '-mbe32'?^M
    Compilation failed.^M
    (gdb) compile code (void) param^M
    arm-none-linux-gnueabihf-gcc: error: unrecognized command line option '-m32'; did you mean '-mbe32'?^M
    Compilation failed.^M
    (gdb) FAIL: gdb.compile/compile-ops.exp: compile code (void) param
    
    This patch fixes it by implementing gcc_target_options gdbarch method
    for arm-linux to override option "-m32".
    
    gdb:
    
    2018-01-19  Yao Qi  <yao.qi@linaro.org>
    
    	* arm-linux-tdep.c (arm_linux_gcc_target_options): New function.
    	(arm_linux_init_abi): Install it.