Don't pass -m32 to libcc1 on arm-linux

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.