rpi3: Move rng driver to drivers

To allow sharing the driver between the RPi3 and RPi4, move the random
number generator driver into the generic driver directory.

Change-Id: Iae94d7cb22c6bce3af9bff709d76d4caf87b14d1
Signed-off-by: Andre Przywara <andre.przywara@arm.com>

include/drivers/rpi3/rng/rpi3_rng.h

+/*
+ * Copyright (c) 2019, Arm Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef RPI3_RNG_H
+#define RPI3_RNG_H
+
+void rpi3_rng_read(void *buf, size_t len);
+
+#endif

plat/rpi/rpi3/platform.mk

 #
-# Copyright (c) 2013-2018, ARM Limited and Contributors. All rights reserved.
+# Copyright (c) 2013-2019, ARM Limited and Contributors. All rights reserved.
 #
 # SPDX-License-Identifier: BSD-3-Clause
 #
@@ -159,7 +159,7 @@ ifeq (${ARCH},aarch32)
 endif
 
 ifneq ($(ENABLE_STACK_PROTECTOR), 0)
-PLAT_BL_COMMON_SOURCES	+=	plat/rpi/rpi3/rpi3_rng.c		\
+PLAT_BL_COMMON_SOURCES	+=	drivers/rpi3/rng/rpi3_rng.c		\
 				plat/rpi/rpi3/rpi3_stack_protector.c
 endif
 

plat/rpi/rpi3/rpi3_private.h

 /*
- * Copyright (c) 2015-2018, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
  *
  * SPDX-License-Identifier: BSD-3-Clause
  */
@@ -33,9 +33,6 @@ uint32_t rpi3_get_spsr_for_bl33_entry(void);
 /* IO storage utility functions */
 void plat_rpi3_io_setup(void);
 
-/* Hardware RNG functions */
-void rpi3_rng_read(void *buf, size_t len);
-
 /* VideoCore firmware commands */
 int rpi3_vc_hardware_get_board_revision(uint32_t *revision);