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/serial/serial_stm32.c b/drivers/serial/serial_stm32.c
index 0160828..a9f5c3c 100644
--- a/drivers/serial/serial_stm32.c
+++ b/drivers/serial/serial_stm32.c
@@ -7,6 +7,7 @@
 #include <common.h>
 #include <clk.h>
 #include <dm.h>
+#include <log.h>
 #include <reset.h>
 #include <serial.h>
 #include <watchdog.h>