docs: serialize_overlap=1 with io_submit_mode=offload no longer requires threads

Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/HOWTO b/HOWTO
index 72ef872..468772d 100644
--- a/HOWTO
+++ b/HOWTO
@@ -2343,7 +2343,7 @@
 	This option only applies to I/Os issued for a single job except when it is
 	enabled along with :option:`io_submit_mode`=offload. In offload mode, fio
 	will check for overlap among all I/Os submitted by offload jobs with :option:`serialize_overlap`
-	enabled. Threads must be used for all such jobs.
+	enabled.
 
 	Default: false.
 
diff --git a/fio.1 b/fio.1
index 7691b2b..ed49268 100644
--- a/fio.1
+++ b/fio.1
@@ -2075,7 +2075,7 @@
 This option only applies to I/Os issued for a single job except when it is
 enabled along with \fBio_submit_mode\fR=offload. In offload mode, fio
 will check for overlap among all I/Os submitted by offload jobs with \fBserialize_overlap\fR
-enabled. Threads must be used for all such jobs.
+enabled.
 .P
 Default: false.
 .RE