common: Drop linux/printk.h from common header

This old patch was marked as deferred. Bring it back to life, to continue
towards the removal of common.h

Move this out of the common header and include it only where needed.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/board/mediatek/mt8518/mt8518_ap1.c b/board/mediatek/mt8518/mt8518_ap1.c
index 2490b15..e03da63 100644
--- a/board/mediatek/mt8518/mt8518_ap1.c
+++ b/board/mediatek/mt8518/mt8518_ap1.c
@@ -8,6 +8,7 @@
 #include <init.h>
 #include <log.h>
 #include <asm/global_data.h>
+#include <linux/printk.h>
 
 DECLARE_GLOBAL_DATA_PTR;