In AArch64 the breakpoint and watchpoint registers are mandatory, so the
kernel always accesses them on bootup. Implement dummy versions, which
read as written but have no actual effect.
Signed-off-by: NPeter Maydell <peter.maydell@linaro.org>
Reviewed-by: NPeter Crosthwaite <peter.crosthwaite@xilinx.com>