uboot-phytec

arm/kirkwood: protect the ENV_SPI #defines

So that they can be redefined by some boards specific values.

Signed-off-by: Valentin Longchamp <valentin.longchamp@keymile.com>
Signed-off-by: Holger Brunck <holger.brunck@keymile.com>
cc: Prafulla Wadaskar <prafulla@marvell.com>