SYSCLK frequency is dependent on on-board switch settings. It may
vary as per requirement. boot-loader is aware of board switch
configurations.

So Fixup Linux device tree from boot-loader.
Signed-off-by: NPrabhakar Kushwaha <prabhakar@freescale.com>
CC: Mingkai Hu <Mingkai.Hu@freescale.com>
Reviewed-by: NYork Sun <york.sun@nxp.com>