configs: Use old hush for several boards

The keymile board family is not compatible with modern hush parser.
Indeed, This boards used set_local_var() to store some variables as local shell.
They then used get_local_var() to retrieve the variables values.
Sadly, this two functions do not exist with CONFIG_HUSH_MODERN_PARSER.
A patch was proposed to use environment variables rather than local variables
but it does not tackle the problem, so complementary work is needed to make
this boards use CONFIG_HUSH_MODERN_PARSER.

Also, with CONFIG_HUSH_MODERN_PARSER, kirkwoord sheevaplug and phytec bk4r1 hit
their board limits, so better to stick with old hush.

Cc: Holger Brunck <holger.brunck@hitachienergy.com>
Link: https://marc.info/?l=u-boot&m=165541917618725&w=2


Signed-off-by: Francis Laniel <francis.laniel@amarulasolutions.com>