imx-mkimage is a host recipe to provide the mkimage_imx8 binaries, required
for the trustfence support with platform based on AHAB (ccimx8x). Since
these binaries are required to the sign process we need to export it in the
SDK to allow the standalone sign mode, and with that we can simplify the
mechanism to share these binaries with another recipes (u-boot, linux).
Also the do_deploy() from imx-mkimage recipe was removed to avoid overriding
the implementation from the native class and allow populating the mkimage
binaries.
Signed-off-by: Arturo Buzarra <arturo.buzarra@digi.com>