refactor(st-clock): remove unused clk function in API

Remove the unused functions in stm32mp clk API:
- stm32mp_stgen_get_counter (change to static, no more exported)
- stm32mp_stgen_restore_counter

Signed-off-by: Patrick Delaunay <patrick.delaunay@foss.st.com>
Change-Id: Ib6ca72723eac3e133f1ca0dee504ef344c72e0bf
2 files changed