staging: greybus: makefile: fix dependency of spi to spilib

Greybus SPI driver depends on gb-spilib and we need to state that at
makefile to make it link correctly.

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
1 file changed