clk: ti: Remove unused functions

They are not used any more since
commit 7558562a ("clk: ti: Drop legacy clk-3xxx-legacy code")

Reported-by: Hulk Robot <hulkci@huawei.com>
Suggested-by: Tero Kristo <t-kristo@ti.com>
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>