common: Drop linux/stringify.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/include/configs/udoo.h b/include/configs/udoo.h
index 163cbbb..54f472d 100644
--- a/include/configs/udoo.h
+++ b/include/configs/udoo.h
@@ -70,6 +70,7 @@
 	func(DHCP, dhcp, na)
 
 #include <config_distro_bootcmd.h>
+#include <linux/stringify.h>
 
 /* Physical Memory Map */
 #define PHYS_SDRAM			MMDC0_ARB_BASE_ADDR