ARM: davinci: SPL: fix BSS initialization

ARM: davinci: SPL: fix BSS initialization

U-Boot README recommends initializing SDRAM in board_init_f(). DA850
was doing it as part of board_init_r() (through call to spl_board_init()
which calls arch_cpu_init() which calls da850_ddr_setup())

This worked fine till commit 15b8c7505819 ("davinci:
da850evm/omapl138-lcdk: Move BSS to SDRAM because SRAM is full") moved
BSS to SDRAM.

Functions like mmc_initialize() called in board_init_r() assume BSS is
available. Since SDRAM was not initialized when arch/arm/lib/crt0.S tried
to initialize BSS to 0, BSS is not initialized correctly.

Fix this by simply calling arch_cpu_init() from board_init_f(). Also move
preloader_console_init() there to help debug issues with board_init_r().

With this spl_board_init() is no longer needed, we remove it.

Tested using MMC/SD boot on OMAP-L138 LCDK board.

Tested-by: Adam Ford <aford173@gmail.com> #da850evm
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Tested-by: Peter Howard <phoward@gme.net.au> #omapl138_lcdk