uboot-imx

sunxi: Remove support for building "old-fashioned" fel binaries

The latest versions of the fel tool support loading normal u-boot builds
directly, and this is now the preferred way to use the fel boot method.

This commit removes support for the old deprecated standalone fel builds.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Ian Campbell <ijc@hellion.org.uk>