Wrap some classes in "namespace gfxstream::guest {}"

... to avoid more duplicate symbol definitions when
building Gfxstream VK ICD.

Bug: b/315317383
Test: deqp-vk w/ Gfxstream ICD
Change-Id: I96b31b8fadec428c94ecc3d5572741cba230c75f
diff --git a/guest/OpenglCodecCommon/ChecksumCalculator.cpp b/guest/OpenglCodecCommon/ChecksumCalculator.cpp
index 123cec7..56d7685 100644
--- a/guest/OpenglCodecCommon/ChecksumCalculator.cpp
+++ b/guest/OpenglCodecCommon/ChecksumCalculator.cpp
@@ -14,10 +14,13 @@
 * limitations under the License.
 */
 
-#include "ChecksumCalculator.h"
+#include "gfxstream/guest/ChecksumCalculator.h"
 
 #include <string.h>
 
+namespace gfxstream {
+namespace guest {
+
 // Checklist when implementing new protocol:
 // 1. update CHECKSUMHELPER_MAX_VERSION
 // 2. update ChecksumCalculator::Sizes enum
@@ -153,3 +156,6 @@
     revLen = (revLen & 0xaaaaaaaa) >> 1 | (revLen & 0x55555555) << 1;
     return revLen;
 }
+
+}  // namespace guest
+}  // namespace gfxstream
\ No newline at end of file