always pull in asm/blackfin.h for Blackfin ports

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
diff --git a/include/common.h b/include/common.h
index 54083f1..e513ab3 100644
--- a/include/common.h
+++ b/include/common.h
@@ -103,6 +103,9 @@
 #ifdef CONFIG_ARM
 #define asmlinkage	/* nothing */
 #endif
+#ifdef CONFIG_BLACKFIN
+#include <asm/blackfin.h>
+#endif
 
 #include <part.h>
 #include <flash.h>