Use of_clk_get_by_name() for timer clocks for DT case.
This patch eliminates a lot of unneeded clk_register_clkdev()
calls for GPT.
Signed-off-by: NAlexander Shiyan <shc_work@mail.ru>
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>