clk: remove davinci dm3xx drivers

The davinci dm3xx machines are all removed, so the clk driver
is no longer needed. The da8xx platforms are now using DT
exclusively, so those drivers remain untouched.

Reviewed-by: David Lechner <david@lechnology.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Acked-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>