patches: add linux/of.h include to st-nci/spi.c

The st-nci/spi.c driver uses some methods from linux/of.h, but does not
explicitly include this file. This is no problem on recent kernel
version, because this file gets included indirectly, on kernel 3.2 it
does not get included indirectly.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>