We want to move the check for watchpoints from
memory_region_section_get_iotlb to tlb_set_page_with_attrs.
Isolate the loop over watchpoints to an exported function.

Rename the existing cpu_watchpoint_address_matches to
watchpoint_address_matches, since it doesn't actually
have a cpu argument.
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Signed-off-by: NRichard Henderson <richard.henderson@linaro.org>