mptcp: kconfig: add default option for BLEST scheduler

Add the possibility to set BLEST as the default scheduler like it is
already possible with the others.

Fixes: 4ffe6a4 ("mptcp: BLocking ESTimation-based (BLEST) Scheduler")
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
(cherry picked from commit 6731697)
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
(cherry picked from commit 8086cd0)
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>

net/mptcp/Kconfig

@@ -134,6 +134,12 @@ choice
 		  This is the redundant scheduler, sending packets redundantly over
 		  all the subflows.
 
+	config DEFAULT_BLEST
+		bool "BLEST" if MPTCP_BLEST=y
+		---help---
+		  This is the BLEST scheduler, sending packets following the
+		  BLocking ESTimation-based algorithm.
+
 endchoice
 endif
 
@@ -143,6 +149,7 @@ config DEFAULT_MPTCP_SCHED
 	default "default" if DEFAULT_SCHEDULER
 	default "roundrobin" if DEFAULT_ROUNDROBIN
 	default "redundant" if DEFAULT_REDUNDANT
+	default "BLEST" if DEFAULT_BLEST
 	default "default"
 
 config MPTCP_DEBUG_LOCK