Staging: fix typo in Makefile

This actually gets the adis16255 driver to build properly.

Cc: Matthias Brugger <mensch0815@googlemail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/Makefile

@@ -49,4 +49,4 @@ obj-$(CONFIG_VIDEO_DT3155)	+= dt3155v4l/
 obj-$(CONFIG_CRYSTALHD)		+= crystalhd/
 obj-$(CONFIG_CXT1E1)		+= cxt1e1/
 obj-$(CONFIG_TI_ST)		+= ti-st/
-obj-$(CONFIG_ADIS16255))		+= adis16255/
+obj-$(CONFIG_ADIS16255)		+= adis16255/