case 6018: reduce the number of blocks written

Reduces the number of blocks written to avoid out of memory errors on some
platforms.

Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/host/xtest/xtest_6000.c b/host/xtest/xtest_6000.c
index f434b35..52def48 100644
--- a/host/xtest/xtest_6000.c
+++ b/host/xtest/xtest_6000.c
@@ -1763,7 +1763,7 @@
 		num_blocks = 20;
 		block_size = 1024;
 	} else {
-		num_blocks = 50;
+		num_blocks = 40;
 		block_size = sizeof(block);
 	}