ARM: i.MX27 clk: Remove clk_register_clkdev() for unused clocks

This patch removes clk_register_clkdev() for the clocks that do not
have any users for non-DT boards and drivers.

Signed-off-by: Alexander Shiyan <shc_work@mail.ru>
Signed-off-by: Shawn Guo <shawn.guo@freescale.com>