Move debug_reg_change_callback and aarch64_notify_debug_reg_change to nat/aarch64...

Move debug_reg_change_callback and aarch64_notify_debug_reg_change to nat/aarch64-linux-hw-point.c

gdb:

2015-08-25  Yao Qi  <yao.qi@linaro.org>

	* aarch64-linux-nat.c (struct arch64_dr_update_callback_param):
	Move it to nat/aarch64-linux-hw-point.c.
	(debug_reg_change_callback): Likewise.
	(aarch64_notify_debug_reg_change): :Likewise.
	* nat/aarch64-linux-hw-point.c: Include nat/linux-nat.h.
	(aarch64_dr_update_callback_param): New.
	(debug_reg_change_callback): New function.
	(aarch64_notify_debug_reg_change): Likewise.
	* nat/aarch64-linux-hw-point.h (aarch64_notify_debug_reg_change):
	Remove the declaration.

gdb/gdbserver:

2015-08-25  Yao Qi  <yao.qi@linaro.org>

	* linux-aarch64-low.c (struct arch64_dr_update_callback_param):
	Remove.
	(debug_reg_change_callback): Remove.
	(aarch64_notify_debug_reg_change): Remove.