ARM: imx: remove unnecessary setting for DSM

Now we support DSM in OCRAM for all i.MX6 SoCs,
the resume entry point is set in asm code of
suspend-imx6.S, so no need to set the resume
entry point for SRC in pre-suspend flow.

Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>