ARM: da850-evm: Increase environment NOR partition offset

The current size allocated to U-Boot is 384k, but U-Boot has grown
to 436K which means that saving the environmental variables wipes
out part of the U-Boot source and the board ceases to function.
Due to the sector and erase size for the NOR part and a desire to
not have to change partition sizes often, this patch moves the
U-Boot environmental variables to an offset of 1M so saveenv
does not brick the board.  This patch also sets up MTDIDS and
MTDPARTS to clearly show where U-Boot and U-Boot's environmental
variables are located.

Signed-off-by: Adam Ford <aford173@gmail.com>