Update the bionic benchmarks documentation.

Test: NA
Change-Id: I6b804a1655b5cb76f189366070d478680f40c5d1
diff --git a/benchmarks/run-on-host.sh b/benchmarks/run-on-host.sh
index bc63628..af96b27 100755
--- a/benchmarks/run-on-host.sh
+++ b/benchmarks/run-on-host.sh
@@ -12,7 +12,7 @@
     )
     exit 0
 elif [ "$1" != 32 -a "$1" != 64 ]; then
-    echo "Usage: $0 [ 32 | 64 | glibc ] [gtest flags]"
+    echo "Usage: $0 [ 32 | 64 | glibc ] [benchmark flags]"
     exit 1
 fi