uboot-imx

microblaze: Fix gd_t address which is placed at the end of BRAM

Setup gd from ASM to be availalbe for board_init_r.
Setting it up in spl_board_init is too late when
MALLOC is used.
Space for gd is located behind MALLOC area at the end of BRAM.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>