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/drivers/mtd/spi/sandbox.c b/drivers/mtd/spi/sandbox.c
index 084c66e..8cbe97e 100644
--- a/drivers/mtd/spi/sandbox.c
+++ b/drivers/mtd/spi/sandbox.c
@@ -12,6 +12,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <log.h>
 #include <malloc.h>
 #include <spi.h>
 #include <os.h>