ARM: bcm2835: remove custom .init_time hook

With arch/arm calling of_clk_init(NULL) from time_init(), we can now
remove custom .init_time hooks. Also remove call to of_clk_init from
clk-bcm2835 with core fixed_clock match, as this has already been
registered now.

Signed-off-by: Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Acked-by: Mike Turquette <mturquette@linaro.org>