clk: mmp: Silence sparse warnings

drivers/clk/mmp/clk-apbc.c:118:16: warning: symbol 'clk_apbc_ops' was not declared. Should it be static?
drivers/clk/mmp/clk-apmu.c:64:16: warning: symbol 'clk_apmu_ops' was not declared. Should it be static?

Cc: Chao Xie <chao.xie@marvell.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>