platform: msm_shared: Move the API to determine the DDR start address to common file.

Move the API to determine the DDR start address by reading the SMEM
partition table to a common file.

Change-Id: I1c3ed483301d4fcea1639a58f9fc49ed9ebda19d
diff --git a/platform/msm_shared/smem.h b/platform/msm_shared/smem.h
index 0edfac6..f6e85a0 100644
--- a/platform/msm_shared/smem.h
+++ b/platform/msm_shared/smem.h
@@ -633,4 +633,5 @@
 uint32_t smem_get_ram_ptable_version(void);
 uint32_t smem_get_ram_ptable_len(void);
 void* smem_get_alloc_entry(smem_mem_type_t type, uint32_t* size);
+uint32_t get_ddr_start();
 #endif				/* __PLATFORM_MSM_SHARED_SMEM_H */