Fix out of order initializer for memory region

Silence out of order initializer compile warnings during memory region
initialization.

Change-Id: Idbbdd93d3ea8cda289d25a473b3882b920b2e8d8

runtime/hsa-runtime/core/inc/amd_memory_region.h

@@ -184,11 +184,11 @@ class MemoryRegion : public core::MemoryRegion {
 
   HsaMemMapFlags map_flag_;
 
-  size_t max_single_alloc_size_;
-
   // Enables creating an extended scope fine grained memory pool region
   const bool extended_scope_fine_grain_;
 
+  size_t max_single_alloc_size_;
+
   // Used to collect total system memory
   static size_t max_sysmem_alloc_size_;