qapi: Correct the name of the iops_rd parameter

Signed-off-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

qapi/block-core.json

@@ -1321,7 +1321,7 @@
 #
 # @iops: total I/O operations per second
 #
-# @ops_rd: read I/O operations per second
+# @iops_rd: read I/O operations per second
 #
 # @iops_wr: write I/O operations per second
 #