New regs_info for aarch32

New regs_info for aarch32

This patch adds a new regs_info regs_info_aarch32 for aarch32, which
can be used by both aarch64 and arm backend.

gdb/gdbserver:

2015-08-04  Yao Qi  <yao.qi@linaro.org>

	* configure.srv (srv_tgtobj): Add linux-aarch32-low.o.
	* linux-aarch32-low.c: New file.
	* linux-aarch32-low.h: New file.
	* linux-arm-low.c (arm_fill_gregset): Move it to
	linux-aarch32-low.c.
	(arm_store_gregset): Likewise.
	(arm_fill_vfpregset): Call arm_fill_vfpregset_num
	(arm_store_vfpregset): Caa arm_store_vfpregset_num.
	(arm_arch_setup): Check if PTRACE_GETREGSET works.
	(regs_info): Rename to regs_info_arm.
	(arm_regs_info): Return regs_info_aarch32 if
	have_ptrace_getregset is 1 and target description is
	arm_with_neon or arm_with_vfpv3.
	(initialize_low_arch): Don't call init_registers_arm_with_neon.
	Call initialize_low_arch_aarch32 instead.