rpi3: Move shared rpi3 files into common directory

To be able to share code more easily between the existing Raspberry Pi 3
and the upcoming Raspberry Pi 4 platform, move some code which is not
board specific into a "common" directory.

Change-Id: I9211ab2d754b040128fac13c2f0a30a5cc8c7f2c
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
diff --git a/plat/rpi/common/include/rpi_shared.h b/plat/rpi/common/include/rpi_shared.h
new file mode 100644
index 0000000..6863438
--- /dev/null
+++ b/plat/rpi/common/include/rpi_shared.h
@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2015-2019, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef RPI_SHARED_H
+#define RPI_SHARED_H
+
+#include <stdint.h>
+
+/*******************************************************************************
+ * Function and variable prototypes
+ ******************************************************************************/
+
+/* Utility functions */
+void rpi3_console_init(void);
+void rpi3_setup_page_tables(uintptr_t total_base, size_t total_size,
+			    uintptr_t code_start, uintptr_t code_limit,
+			    uintptr_t rodata_start, uintptr_t rodata_limit
+#if USE_COHERENT_MEM
+			    , uintptr_t coh_start, uintptr_t coh_limit
+#endif
+			    );
+
+/* Optional functions required in the Raspberry Pi 3 port */
+unsigned int plat_rpi3_calc_core_pos(u_register_t mpidr);
+
+/* BL2 utility functions */
+uint32_t rpi3_get_spsr_for_bl32_entry(void);
+uint32_t rpi3_get_spsr_for_bl33_entry(void);
+
+/* IO storage utility functions */
+void plat_rpi3_io_setup(void);
+
+/* VideoCore firmware commands */
+int rpi3_vc_hardware_get_board_revision(uint32_t *revision);
+
+#endif /* RPI3_PRIVATE_H */