clk: mvebu: cp110: Minor cleanups

Mark an array of strings static const and remove the dereference
of a function pointer when assigning to the platform driver probe
struct member.

drivers/clk/mvebu/cp110-system-controller.c:89:12:
warning: symbol 'gate_base_names' was not declared. Should it be static?
drivers/clk/mvebu/cp110-system-controller.c:447:18:
error: cannot dereference this type

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>