Remove concept of top/bottom image loading

This concept is no longer required since we now support loading of
images at fixed addresses only.

The image loader now automatically detects the position of the image
inside the current memory layout and updates the layout such that
memory fragmentation is minimised.

The 'attr' field of the meminfo data structure, which used to hold
the bottom/top loading information, has been removed. Also the 'next'
field has been removed as it wasn't used anywhere.

The 'init_bl2_mem_layout()' function has been moved out of common
code and put in BL1-specific code. It has also been renamed into
'bl1_init_bl2_mem_layout'.

Fixes ARM-software/tf-issues#109

Change-Id: I3f54642ce7b763d5ee3b047ad0ab59eabbcf916d
diff --git a/include/plat/common/platform.h b/include/plat/common/platform.h
index c087dc6..c130ae7 100644
--- a/include/plat/common/platform.h
+++ b/include/plat/common/platform.h
@@ -90,10 +90,8 @@
 /*******************************************************************************
  * Optional BL1 functions (may be overridden)
  ******************************************************************************/
-void init_bl2_mem_layout(struct meminfo *,
-			struct meminfo *,
-			unsigned int,
-			unsigned long);
+void bl1_init_bl2_mem_layout(const struct meminfo *bl1_mem_layout,
+			     struct meminfo *bl2_mem_layout);
 
 /*******************************************************************************
  * Mandatory BL2 functions