ahci: imx: add missing clk_disable_unprepare() on error in imx_sata_enable()

Add the missing clk_disable_unprepare() before return from
imx_sata_enable() in the phy reset error handling case.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Acked-by: Shawn Guo <shawn.guo@freescale.com>
Signed-off-by: Tejun Heo <tj@kernel.org>