Add in the Makefile bits for the new intel gma driver

The Intel GMA driver is in, this CL splices in the Makefile bits.

Change-Id: Icf42a537575b8cc90a679ec1fc15b09294630611
Signed-off-by: Ronald G. Minnich <rminnich@google.com>
Reviewed-on: https://gerrit.chromium.org/gerrit/60346
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Commit-Queue: Ronald G. Minnich <rminnich@chromium.org>
Tested-by: Ronald G. Minnich <rminnich@chromium.org>
Reviewed-on: http://review.coreboot.org/4331
Tested-by: build bot (Jenkins)
Reviewed-by: Alexandru Gagniuc <mr.nuke.me@gmail.com>
diff --git a/src/drivers/Makefile.inc b/src/drivers/Makefile.inc
index da397d0..7b1e4ca 100644
--- a/src/drivers/Makefile.inc
+++ b/src/drivers/Makefile.inc
@@ -22,6 +22,7 @@
 subdirs-y += emulation
 subdirs-y += generic
 subdirs-y += i2c
+subdirs-y += intel
 subdirs-y += maxim
 subdirs-y += oxford
 subdirs-y += parade