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/pwm/pwm-imx.c b/drivers/pwm/pwm-imx.c
index 8d8f3e6..f5b9544 100644
--- a/drivers/pwm/pwm-imx.c
+++ b/drivers/pwm/pwm-imx.c
@@ -9,6 +9,7 @@
 #include <common.h>
 #include <div64.h>
 #include <dm.h>
+#include <log.h>
 #include <pwm.h>
 #include <asm/arch/imx-regs.h>
 #include <asm/io.h>