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_pm.c b/plat/amlogic/gxl/gxl_pm.c
index 4a5d26e..544ae20 100644
--- a/plat/amlogic/gxl/gxl_pm.c
+++ b/plat/amlogic/gxl/gxl_pm.c
@@ -15,7 +15,7 @@
 #include <platform_def.h>
 #include <lib/psci/psci.h>
 
-#include "gxl_private.h"
+#include "aml_private.h"
 
 #define SCPI_POWER_ON		0
 #define SCPI_POWER_RETENTION	1