clk: mediatek: Fix memory leaks on probe

Handle the error branches to free memory where required.

Addresses-Coverity-ID: 1491825 ("Resource leak")
Signed-off-by: José Expósito <jose.exposito89@gmail.com>
Reviewed-by: Chen-Yu Tsai <wenst@chromium.org>
Link: https://lore.kernel.org/r/20220115183059.GA10809@elementary


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