arm: mach-omap2: Factor out common FDT fixup suport

Some of the fixups currently done for OMAP5 class boards are common to
other OMAP family devices, move these to fdt-common.c.

Signed-off-by: Andrew F. Davis <afd@ti.com>

arch/arm/include/asm/omap_sec_common.h

@@ -27,6 +27,12 @@ u32 secure_rom_call(u32 service, u32 proc_id, u32 flag, ...);
  */
 int secure_boot_verify_image(void **p_image, size_t *p_size);
 
+/*
+ * Return the start of secure reserved RAM, if a default start address has
+ * not been configured then return a region at the end of the external DRAM.
+ */
+u32 get_sec_mem_start(void);
+
 /*
  * Invoke a secure HAL API that allows configuration of the external memory
  * firewall regions.