Use explicit .c_str() for hidl_string

hidl_string no longer will provide an implicit cast to const char* as it
interfers with other expected behaviors of the class.  It now emulates
std::string in requiring a call to .c_str() to get the same behavior.

Bug:  36532780
Test:  Build the tree
Change-Id: Ia6c4f7c33bed20cf523a3802d7aab9570c7e54eb
1 file changed
tree: 7181f0c5addc841aba59377ea190068d52137085
  1. wifi/
  2. Android.bp
  3. update-makefiles.sh