mk: replace the combined library with a linker script

mk: replace the combined library with a linker script

The physically linked-together combined library has been an increasing
source of problems, as was predicted when library and symbol versioning
was introduced. Replace the complex and fragile construction with a
simple linker script which achieves the same without all the problems,
remove the related kludges from eg mlx drivers.

Since creating the linker script is practically zero cost, remove the
config option and just create it always.

Based on a patch by Sergio Gonzales Monroy, linker script approach
initially suggested by Neil Horman.

Suggested-by: Sergio Gonzalez Monroy <sergio.gonzalez.monroy@intel.com>
Suggested-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Panu Matilainen <pmatilai@redhat.com>
Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>