This patch adds the a4m2k MPC5200B board port. Its a derivate of
the a3m071 board with only minor changes.
Additionally this patch includes some clean-up changes:
- Remove I2C support from a3m071 as its unused
- Fix/enhance default env variables
- Fix some comments
- Add newly introduced CONFIG_SPL_TARGET to automatically build
- Fix dtb patching in READ desciption for SPL Linux booting:
"fdt chosen" needs to get called to patch/create the chosen node.
- Add missing call to spl_board_init():
Define CONFIG_SPL_BOARD_INIT so that spl_board_init() will get
called in the SPL version.
Signed-off-by: Stefan Roese <firstname.lastname@example.org>