common: Drop log.h from common header

Move this header out of the common header.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/st/stm32f746-disco/stm32f746-disco.c b/board/st/stm32f746-disco/stm32f746-disco.c
index df90742..ae5e110 100644
--- a/board/st/stm32f746-disco/stm32f746-disco.c
+++ b/board/st/stm32f746-disco/stm32f746-disco.c
@@ -8,6 +8,7 @@
 #include <dm.h>
 #include <init.h>
 #include <lcd.h>
+#include <log.h>
 #include <miiphy.h>
 #include <phy_interface.h>
 #include <ram.h>