oem-ibm: make DMA max size configurable

Signed-off-by: Deepak Kodihalli <dkodihal@in.ibm.com>
Change-Id: I3dd6f30db4bbf7b6290362b32a4e6e42ef993705
diff --git a/oem/ibm/libpldmresponder/file_io.hpp b/oem/ibm/libpldmresponder/file_io.hpp
index 3a504bf..4e0cad4 100644
--- a/oem/ibm/libpldmresponder/file_io.hpp
+++ b/oem/ibm/libpldmresponder/file_io.hpp
@@ -1,5 +1,7 @@
 #pragma once
 
+#include "config.h"
+
 #include "handler.hpp"
 #include "utils.hpp"
 
@@ -26,8 +28,7 @@
 // The minimum data size of dma transfer in bytes
 constexpr uint32_t minSize = 16;
 
-// 16MB - 4096B (16773120 bytes) is the maximum data size of DMA transfer
-constexpr size_t maxSize = (16 * 1024 * 1024) - 4096;
+constexpr size_t maxSize = DMA_MAXSIZE;
 
 namespace fs = std::filesystem;