Fixed that telephony registry service reference incorrectly assigned

The reference to telephony registry service was assigned
prior telephony registry service was ready. Fixed by
casting the binder every time when we use it.

Test: Manual
Bug: 65593241
Merged-In: Ib234cdfd93130f7af44ef79271b106fffb8ebad5
Change-Id: Ib234cdfd93130f7af44ef79271b106fffb8ebad5
(cherry picked from commit 66420e25)