amlogic: Introduce unified private header file

Now that also the SHA256 DMA driver is shared between all the SoCs, we
can have one single private platform header file.

Signed-off-by: Carlo Caione <ccaione@baylibre.com>
Change-Id: I77d51915f9d8233aeceeed66ed1f491573402cfc
diff --git a/plat/amlogic/gxl/gxl_bl31_setup.c b/plat/amlogic/gxl/gxl_bl31_setup.c
index b1da794..ddf43c9 100644
--- a/plat/amlogic/gxl/gxl_bl31_setup.c
+++ b/plat/amlogic/gxl/gxl_bl31_setup.c
@@ -13,7 +13,7 @@
 #include <lib/mmio.h>
 #include <lib/xlat_tables/xlat_mmu_helpers.h>
 
-#include "gxl_private.h"
+#include "aml_private.h"
 
 /*
  * Placeholder variables for copying the arguments that have been passed to