common: Drop linux/bug.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/sifive/fu540/fu540.c b/board/sifive/fu540/fu540.c
index d2a1ed0..df57b6e 100644
--- a/board/sifive/fu540/fu540.c
+++ b/board/sifive/fu540/fu540.c
@@ -10,6 +10,7 @@
 #include <dm.h>
 #include <env.h>
 #include <init.h>
+#include <linux/bug.h>
 #include <linux/delay.h>
 #include <linux/io.h>