cpu: move adjust_watchpoint_address to tcg_ops

cpu: move adjust_watchpoint_address to tcg_ops

commit 40612000599e ("arm: Correctly handle watchpoints for BE32 CPUs")

introduced this ARM-specific, TCG-specific hack to adjust the address,
before checking it with cpu_check_watchpoint.

Make adjust_watchpoint_address optional and move it to tcg_ops.

Signed-off-by: Claudio Fontana <cfontana@suse.de>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20210204163931.7358-14-cfontana@suse.de>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>