drivers:staging:solo6x10:add the missed slab.h

Add the missed linux/slab.h to solo6x10.h.

Signed-off-by: Wanlong Gao <gaowanlong@cn.fujitsu.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/solo6x10/solo6x10.h b/drivers/staging/solo6x10/solo6x10.h
index 17c06bd..abee721 100644
--- a/drivers/staging/solo6x10/solo6x10.h
+++ b/drivers/staging/solo6x10/solo6x10.h
@@ -28,6 +28,7 @@
 #include <linux/list.h>
 #include <linux/wait.h>
 #include <linux/delay.h>
+#include <linux/slab.h>
 #include <asm/io.h>
 #include <linux/atomic.h>
 #include <linux/videodev2.h>