This eliminates the need to traverse value chain, doing
various checks, in three different places.
* breakpoint.h (struct bp_location): New fields
lengths and watchpoint_type.
(struct breakpoint): Remove the val_chain field.
* breakpoint.c (is_hardware_watchpoint): New.
(free_valchain): Remove.
(update_watchpoint): New.
(insert_bp_location): For hardware watchpoint, just
directly insert it.
(insert_breakpoints): Call update_watchpoint_locations
on all watchpoints. If we have failed to insert
any location of a hardware watchpoint, remove all inserted
locations.
(remove_breakpoint): For hardware watchpoints, directly
remove location.
(watchpoints_triggered): Iterate over locations.
(bpstat_stop_status): Use only first location of
a resource watchpoint.
(delete_breakpoint): Don't call free_valchain.
(print_one_breakpoint): Don't print all
locations for watchpoints.
(breakpoint_re_set_one): Use update_watchpoint for
watchpoints.
