powerpc/mpc8536ds: Save the env variables to SDcard and SPI flash
MPC8536DS offer booting from SDcard or SPI flash. This patch defined that
u-boot can save the environment variables on SDcard or SPI flash when
booting from the related device. The Env parameter region and linux
kernel region have overlap in SPI-Flash, So change the Env param saving
address.
Signed-off-by: Xie Xiaobo <r63061@freescale.com> Signed-off-by: Kumar Gala <galak@kernel.crashing.org>