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/spi/tegra20_slink.c b/drivers/spi/tegra20_slink.c
index ae2fc3e..f09d960 100644
--- a/drivers/spi/tegra20_slink.c
+++ b/drivers/spi/tegra20_slink.c
@@ -7,6 +7,7 @@
 
 #include <common.h>
 #include <dm.h>
+#include <log.h>
 #include <time.h>
 #include <asm/io.h>
 #include <asm/arch/clock.h>