regression 6018: reduce the number of blocks written

Reduces the number of blocks written when testing REE filesystem to
avoid occasional out of memory errors.

Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/host/xtest/regression_6000.c b/host/xtest/regression_6000.c
index ee37c5b..b987bf6 100644
--- a/host/xtest/regression_6000.c
+++ b/host/xtest/regression_6000.c
@@ -1716,7 +1716,7 @@
 		num_blocks = 10;
 		block_size = 1024;
 	} else {
-		num_blocks = 40;
+		num_blocks = 20;
 		block_size = sizeof(block);
 	}