uboot-imx

misc: fs_loader: Use device_get_global_by_ofnode to get to node

Instead of two staged ofnode_to_offset followed by
device_get_global_by_of_offset approach, direcly use the
device_get_global_by_ofnode to fetch the device.

Signed-off-by: Keerthy <j-keerthy@ti.com>
Reviewed-by: Simon Glass <sjg@chromium.org>