ARM: dts: imx53: correct clock-names of SATA node

Per the binding doc imx-sata.txt, the first entry of clock-names should
be "sata" than anything else.  Correct it for imx53 SATA node.

It works for now only because SATA driver gets clock by index so far.

Signed-off-by: Shawn Guo <shawn.guo@freescale.com>