common: Drop linux/delay.h from common header

Move this uncommon header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/drivers/fpga/virtex2.c b/drivers/fpga/virtex2.c
index 3957368..b3e0537 100644
--- a/drivers/fpga/virtex2.c
+++ b/drivers/fpga/virtex2.c
@@ -15,6 +15,7 @@
 #include <common.h>
 #include <console.h>
 #include <virtex2.h>
+#include <linux/delay.h>
 
 #if 0
 #define FPGA_DEBUG