Export maximum affinity using PLATFORM_MAX_AFFLVL macro

This patch removes the plat_get_max_afflvl() platform API
and instead replaces it with a platform macro PLATFORM_MAX_AFFLVL.
This is done because the maximum affinity level for a platform
is a static value and it is more efficient for it to be defined
as a platform macro.

NOTE: PLATFORM PORTS NEED TO BE UPDATED ON MERGE OF THIS COMMIT

Fixes ARM-Software/tf-issues#265

Change-Id: I31d89b30c2ccda30d28271154d869060d50df7bf
diff --git a/plat/fvp/include/platform_def.h b/plat/fvp/include/platform_def.h
index 326ba9d..fcecc56 100644
--- a/plat/fvp/include/platform_def.h
+++ b/plat/fvp/include/platform_def.h
@@ -105,6 +105,7 @@
 #define PLATFORM_MAX_CPUS_PER_CLUSTER	4
 #define PLATFORM_NUM_AFFS		(PLATFORM_CLUSTER_COUNT + \
 					 PLATFORM_CORE_COUNT)
+#define PLATFORM_MAX_AFFLVL		MPIDR_AFFLVL1
 #define MAX_IO_DEVICES			3
 #define MAX_IO_HANDLES			4