Get rid of tBTA_DM_SEARCH_CB.services

This was set either to either 0 or BTA_ALL_SERVICE_MASK, and used when
name and service discovery was one function, no longer needed.

Bug: 330675788
Flag: exempt, trivial
Test: mma -j32
Change-Id: Ib7815fd9eb7768ad5decfc0bb143f93e5ae0cd35