Always use named structs in header files

Add tag names to all unnamed structs in header files. This
allows forward declaration of structs, which is necessary to
reduce header file nesting (to be implemented in a subsequent
commit).

Also change the typedef names across the codebase to use the _t
suffix to be more conformant with the Linux coding style. The
coding style actually prefers us not to use typedefs at all but
this is considered a step too far for Trusted Firmware.

Also change the IO framework structs defintions to use typedef'd
structs to be consistent with the rest of the codebase.

Change-Id: I722b2c86fc0d92e4da3b15e5cab20373dd26786f
diff --git a/include/bl1/bl1.h b/include/bl1/bl1.h
index e1d50c0..1750a1f 100644
--- a/include/bl1/bl1.h
+++ b/include/bl1/bl1.h
@@ -39,7 +39,7 @@
  * Function prototypes
  *****************************************/
 extern void bl1_platform_setup(void);
-extern meminfo *bl1_plat_sec_mem_layout(void);
+extern meminfo_t *bl1_plat_sec_mem_layout(void);
 
 #endif /*__ASSEMBLY__*/