enum lwp_stop_reason -> enum target_stop_reason

enum lwp_stop_reason -> enum target_stop_reason

We're going to need the same enum as enum lwp_stop_reason in more
targets, so this promotes it to common code.

gdb/gdbserver/ChangeLog:
2015-03-04  Pedro Alves  <palves@redhat.com>

	enum lwp_stop_reason -> enum target_stop_reason
	* linux-low.c (check_stopped_by_breakpoint): Adjust.
	(thread_still_has_status_pending_p, check_stopped_by_watchpoint)
	(linux_wait_1, stuck_in_jump_pad_callback)
	(move_out_of_jump_pad_callback, linux_resume_one_lwp)
	(linux_stopped_by_watchpoint):
	* linux-low.h (enum lwp_stop_reason): Delete.
	(struct lwp_info) <stop_reason>: Now an enum target_stop_reason.
	* linux-x86-low.c (x86_linux_prepare_to_resume): Adjust.

gdb/ChangeLog:
2015-03-04  Pedro Alves  <palves@redhat.com>

	enum lwp_stop_reason -> enum target_stop_reason
	* linux-nat.c (linux_resume_one_lwp, check_stopped_by_watchpoint)
	(linux_nat_stopped_by_watchpoint, status_callback)
	(linux_nat_wait_1): Adjust.
	* linux-nat.h (enum lwp_stop_reason): Delete.
	(struct lwp_info) <stop_reason>: Now an enum target_stop_reason.
	* x86-linux-nat.c (x86_linux_prepare_to_resume): Adjust.
	* target/waitstatus.h (enum target_stop_reason): New.