corrections for MAX77686 config variable

Fix some minor discrepancies which prevented the MAX77676 from
getting compiled in properly.

Change-Id: Ib29136da6c15a4bdb24926a91729431c507cd209
Signed-off-by: David Hendricks <dhendrix@chromium.org>
Reviewed-on: http://review.coreboot.org/2076
Tested-by: build bot (Jenkins)
Reviewed-by: Hung-Te Lin <hungte@chromium.org>
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>
diff --git a/src/drivers/maxim/Makefile.inc b/src/drivers/maxim/Makefile.inc
index 31c3d75..578f659 100644
--- a/src/drivers/maxim/Makefile.inc
+++ b/src/drivers/maxim/Makefile.inc
@@ -17,4 +17,4 @@
 ## Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 ##
 
-subdirs-$(CONFIG_DRIVERS_MAXIM_MAX77676) += max77686
+subdirs-$(CONFIG_DRIVER_MAXIM_MAX77686) += max77686/