plat/arm/arm_image_load: refine plat_add_sp_images_load_info
plat/arm/arm_image_load: refine plat_add_sp_images_load_info

Refine the function plat_add_sp_images_load_info() by saving the
previous node and only setting its next link when the current node is
valid. This can reduce the check for the next node and simply the
total logic.

Signed-off-by: Heyi Guo <554902d6d74fca466aa06b42f6ec0849d7c72a90@linux.alibaba.com>
Change-Id: I4061428bf49ef0c3816ac22aaeb2e50315531f88

achingupta/arm-trusted-firmware,achingupta/arm-trusted-firmware