Fixes the previous TLB_WATCHPOINT patches because we are currently
failing to set cpu->mem_io_pc with the call to cpu_check_watchpoint.
Pass down the retaddr directly because it's readily available.

Fixes: 50b107c5Reviewed-by: NAlex Bennée <alex.bennee@linaro.org>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>