Add README for the "Falcon" mode

Simple howto to add support to a board
for booting the kernel from SPL ("Falcon" mode).

Signed-off-by: Stefano Babic <sbabic@denx.de>
Reviewed-by: Tom Rini <trini@ti.com>
OMAP3: drop CONFIG_SPL_OS_BOOT_KEY and use local define

CONFIG_SPL_OS_BOOT_KEY is used only in board files. It is
not required to have a general CONFIG_ option. Rename it and
define it in board directory.

Signed-off-by: Stefano Babic <sbabic@denx.de>
Reviewed-by: Tom Rini <trini@ti.com>
SPL: Change description for spl command

Add a more descriptive text to the help of the spl
command.

Signed-off-by: Stefano Babic <sbabic@denx.de>
Reviewed-by: Tom Rini <trini@ti.com>