Include break-common.h in nat/aarch64-linux-hw-point.h

Include break-common.h in nat/aarch64-linux-hw-point.h

$ make check-headers CHECK_HEADERS="nat/aarch64-linux-hw-point.h"
...
../../binutils-gdb/gdb/nat/aarch64-linux-hw-point.h:169:37: error: use of enum 'target_hw_bp_type' without previous declaration
 int aarch64_handle_breakpoint (enum target_hw_bp_type type, CORE_ADDR addr,
                                     ^
gdb:

2017-01-06  Yao Qi  <yao.qi@linaro.org>

	* nat/aarch64-linux-hw-point.h: Include break-common.h.