clk: cdce706: Add missing of_clk_del_provider call in cdce706_remove

Remove a previously registered clock provider when unload the module.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Acked-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>