spl: fix assignment of board info to global data

Commit 15eb1d43 ("spl: reorder the assignment of board info to
global data") intended to move assignment of board info earlier,
into board_init_r(). However, function preload_console_init() is
called either from spl_board_init() or from board_init_f(). For the
latter case, the board info assignment is much earlier than proposed
board_init_r(). Create a new function to fill gd->bd and call this
function when needed.

Signed-off-by: York Sun <york.sun@nxp.com>
CC: Lokesh Vutla <lokeshvutla@ti.com>
CC: Ravi Babu <ravibabu@ti.com>
CC: Lukasz Majewski <lukma@denx.de>
CC: Tom Rini <trini@konsulko.com>
Reviewed-by: Simon Glass <sjg@chromium.org>