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/pcm052.h b/include/configs/pcm052.h
index 0bfaaf7..ba7aad8 100644
--- a/include/configs/pcm052.h
+++ b/include/configs/pcm052.h
@@ -10,6 +10,7 @@
 
 #include <asm/arch/imx-regs.h>
 #include <linux/sizes.h>
+#include <linux/stringify.h>
 
 #define CONFIG_SKIP_LOWLEVEL_INIT