Remove redundant dependency on libpower

* libpower dependency was introduced in change
  I1e8d49b087eff6301373e1e90e8d868f15847c34
* It is never used in any part of the system/bt stack and therefore
  should be removed from the shared library dependency list

Bug: 34079981
Test: code compilation, no user visible effect
Change-Id: Ic8e3ad0c369839fb9ced446695c72fdf0ffad1ca