[arm] use target_mgreg_t instead of plain pointer type in sdb breakpoint (#15205)
[arm] use target_mgreg_t instead of plain pointer type in sdb breakpoint
Fixes Debug mode for iOS 32bit.
Contributes to https://github.com/mono/mono/issues/15058 & https://github.com/mono/mono/issues/9621
Diff before (left old cross32, right new cross32 running on amd64 host _before_ this fix):
<img width="1257" alt="Screenshot 2019-06-17 at 14 09 51" src="https://user-images.githubusercontent.com/75403/
59603413-
a9bd4f00-9109-11e9-8f18-
aa7b4ca5817f.png">
/cc @mandel-macaque