Fix CameraParameters2::OrderedKeyedVector::removeItem tautological-compare

The tautological-compare warning/error is uncovered when
frameworks/av/include is moved from being a system header directory to a
normal include directory.

Test: m -j checkbuild
Change-Id: Ie2d6c354f11e162416a1ac5e8ea185fa62a959a0
diff --git a/include/camera/CameraParameters2.h b/include/camera/CameraParameters2.h
index 88ad812..f691cd6 100644
--- a/include/camera/CameraParameters2.h
+++ b/include/camera/CameraParameters2.h
@@ -151,7 +151,7 @@
         }
 
         ssize_t removeItem(const KeyT& key) {
-            size_t vectorIdx = (size_t) indexOfKey(key);
+            ssize_t vectorIdx = indexOfKey(key);
 
             if (vectorIdx < 0) {
                 return vectorIdx;