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/xilinx/zynq/cmds.c b/board/xilinx/zynq/cmds.c
index 3358934..1098466 100644
--- a/board/xilinx/zynq/cmds.c
+++ b/board/xilinx/zynq/cmds.c
@@ -5,6 +5,7 @@
 
 #include <common.h>
 #include <command.h>
+#include <log.h>
 #include <asm/io.h>
 #include <asm/arch/hardware.h>
 #include <asm/arch/sys_proto.h>