clk: imx: Replace clk error check with imx_check_clocks()

As we already have a 'imx_check_clocks' to do the clock error
check, so cleanup the error check code.

Signed-off-by: Bai Ping <b51503@freescale.com>
Acked-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>