sf: Add spi_boot() to allow booting from SPI flash in an SPL

Signed-off-by: Christian Riesch <christian.riesch@omicron.at>
Cc: Heiko Schocher <hs@denx.de>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Scott Wood <scottwood@freescale.com>
Acked-by: Mike Frysinger <vapier@gentoo.org>
4 files changed