meta-phosphor: add raspberrypi folder: add linux-kernel gpio-key patch

Add raspberrypi folder in meta-phosphor match phosphor related
package.

Add phosphor-gpio-keys cfg for build phosphor related kernel.

Change-Id: Ia3964629abc2d8f83d20d227f901a63f15927372
Signed-off-by: Samuel Jiang <chyishian.jiang@gmail.com>
diff --git a/raspberrypi/recipes-kernel/linux/linux-raspberrypi/phosphor-gpio-keys.scc b/raspberrypi/recipes-kernel/linux/linux-raspberrypi/phosphor-gpio-keys.scc
new file mode 100644
index 0000000..78961af
--- /dev/null
+++ b/raspberrypi/recipes-kernel/linux/linux-raspberrypi/phosphor-gpio-keys.scc
@@ -0,0 +1,2 @@
+define KFEATURE_DESCRIPTION "Enable gpio-keys"
+kconf non-hardware phosphor-gpio-keys.cfg