ARM: nomadik: remove mtu initalization from .init_time

Nomadik clock initialization is properly done in clk-nomadik since
patch "clk: nomadik: set all timers to use 2.4 MHz TIMCLK".
Therefore, this patch removes now redundant mtu initialization from
.init_time callback.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>