fsl_sec : Change accessor function to take care of endianness

SEC registers can be of type Little Endian or big Endian depending upon
Freescale SoC. Here SoC defines the register type of SEC IP.

So update acessor functions with common SEC acessor functions to take care
both type of endianness.

Signed-off-by: Ruchika Gupta <ruchika.gupta@freescale.com>
Reviewed-by: York Sun <yorksun@freescale.com>