Refactor and enhance break/watchpoint API (Jan Kiszka)

Refactor and enhance break/watchpoint API (Jan Kiszka)

This patch prepares the QEMU cpu_watchpoint/breakpoint API to allow the
succeeding enhancements this series comes with.

First of all, it overcomes MAX_BREAKPOINTS/MAX_WATCHPOINTS by switching
to dynamically allocated data structures that are kept in linked lists.
This also allows to return a stable reference to the related objects,
required for later introduced x86 debug register support.

Breakpoints and watchpoints are stored with their full information set
and an additional flag field that makes them easily extensible for use
beyond pure guest debugging.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5738 c046a42c-6fe2-441c-8c8c-71466251a162