powerpc/85xx: introduce corenet_generic machine

In the current kernel, the board files for p2041rdb, p3041ds, p4080ds,
p5020ds, p5040ds, t4240qds and b4qds are almost the same except the
machine name. So this introduces a cornet_generic machine to support
all these boards to avoid the code duplication.

With these changes the file corenet_ds.h becomes useless. Just delete
it.

Signed-off-by: Kevin Hao <haokexin@gmail.com>
Signed-off-by: Scott Wood <scottwood@freescale.com>

diff --cc arch/powerpc/platforms/85xx/Kconfig
Simple merge

diff --cc arch/powerpc/platforms/85xx/Makefile
Simple merge

diff --cc arch/powerpc/platforms/85xx/b4_qds.c
Simple merge

diff --cc arch/powerpc/platforms/85xx/corenet_ds.c
Simple merge

diff --cc arch/powerpc/platforms/85xx/corenet_ds.h
Simple merge

diff --cc arch/powerpc/platforms/85xx/p2041_rdb.c
Simple merge

diff --cc arch/powerpc/platforms/85xx/p3041_ds.c
Simple merge

diff --cc arch/powerpc/platforms/85xx/p4080_ds.c
Simple merge

diff --cc arch/powerpc/platforms/85xx/p5020_ds.c
Simple merge

diff --cc arch/powerpc/platforms/85xx/p5040_ds.c
Simple merge

diff --cc arch/powerpc/platforms/85xx/t4240_qds.c
Simple merge