fix(xilinx): add FIT image check in prepare_dtb

Introduce two new functions: 'is_valid_image()' and 'is_fit_image()'
to enhance the functionality of the system. 'is_valid_image()' will
verify the presence of the FDT header and ensure that the FDT is
open. Meanwhile, 'is_fit_image()' will be responsible for detecting
FIT images. When TF-A is built with a DTB address during compilation
and later executed from DDR memory, TF-A will dynamically reserve a
memory location in the DTB during runtime.

This approach is effective when a raw DTB is present at the specified
address location. With this change, the "is_fit_image()" function
has been introduced to verify the existence of the "/configurations"
property within the DTB.

The presence of this property is exclusive to FIT images. In case
the property is found, a warning message is displayed, and memory
space reservation for its address space in DDR is not performed by
TF-A. However, if the property is not present, TF-A continues its
usual procedure of updating the raw DTB.

Additionally, dynamic mapping has been refactored and separated into
distinct functions: "add_mmap_dynamic_region ()" and
"remove_dynamic_mmap()". This separation enhances compatibility
and maintains better code organization.

Change-Id: I9cd3f09863b44483445e58c802dee34d58dfe2e9
Signed-off-by: Prasad Kummari <prasad.kummari@amd.com>
diff --git a/plat/xilinx/common/include/plat_fdt.h b/plat/xilinx/common/include/plat_fdt.h
index a1ee1e1..47a678c 100644
--- a/plat/xilinx/common/include/plat_fdt.h
+++ b/plat/xilinx/common/include/plat_fdt.h
@@ -9,4 +9,8 @@
 
 void prepare_dtb(void);
 
+#if defined(XILINX_OF_BOARD_DTB_ADDR)
+int32_t is_valid_dtb(void *fdt);
+#endif
+
 #endif /* PLAT_FDT_H */