Adjust IMapperMetadataTypes.h to match gralloc4 encoding

Specifically include the header encoding. Initially
omitted as it's a bit redundant, the value in having
bit-for-bit identical encoding between gralloc4 &
imapper5 seems worthwhile enough to keep it.

Test: impltests + VtsHalGraphicsMapperStableC
Change-Id: Iee37bb97acf40362c301a06f9118938b1a0c2cd9
diff --git a/graphics/mapper/stable-c/vts/VtsHalGraphicsMapperStableC_TargetTest.cpp b/graphics/mapper/stable-c/vts/VtsHalGraphicsMapperStableC_TargetTest.cpp
index 326346c..85246ee 100644
--- a/graphics/mapper/stable-c/vts/VtsHalGraphicsMapperStableC_TargetTest.cpp
+++ b/graphics/mapper/stable-c/vts/VtsHalGraphicsMapperStableC_TargetTest.cpp
@@ -234,7 +234,7 @@
             sizeRequired = mapper()->v5.getStandardMetadata(bufferHandle, static_cast<int64_t>(T),
                                                             buffer.data(), buffer.size());
         }
-        if (sizeRequired < 0 || sizeRequired >= buffer.size()) {
+        if (sizeRequired < 0 || sizeRequired > buffer.size()) {
             ADD_FAILURE() << "getStandardMetadata failed, received " << sizeRequired
                           << " with buffer size " << buffer.size();
             // Generate a fail type