Correct the comparison to match the signedness

Change-Id: I25dfa2c8fb77e9e6d729ccc044b75d74adbf7e5e
Signed-off-by: Tom Joseph <tomjoseph@in.ibm.com>
diff --git a/libpldmresponder/file_io.cpp b/libpldmresponder/file_io.cpp
index 1ebedfd..adcccac 100644
--- a/libpldmresponder/file_io.cpp
+++ b/libpldmresponder/file_io.cpp
@@ -87,7 +87,7 @@
         stream.seekg(offset);
         stream.read(static_cast<char*>(vgaMemPtr.get()), length);
 
-        if (stream.gcount() != length)
+        if (static_cast<uint32_t>(stream.gcount()) != length)
         {
             log<level::ERR>("mismatch between number of characters to read and "
                             "the length read",