nyan-big: change spi delay

Internal keyboard of nyan-big is only working when cold booting by pressing [reload/refresh]+[power] button.
With this patch keyboard is working by only pressing [power] button.

Signed-off-by: Tristan Bastian <tristan-c.bastian@gmx.de>
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>