uboot-phytec

arm/km: remove portl2.h and use km_kirkwood instead

The additional headerfile is unneeded here, we can use the generic
km_kirkwood.h instead. And we can use the better config option
KM_PIGGY4_88E6061 for the specific features for boards with this
design in km_arm.c.

Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
cc: Gerlando Falauto <gerlando.falauto@keymile.com>
cc: Prafulla Wadaskar <prafulla@marvell.com>