Check BR device count before initiating role switch

A case where DUT is acting as PANU device on BR/EDR link & also
acting as central on LE link. As LE link & PANU link need not to
be master & it's not a scatter-net scenario, because there is only
a BR link. So checking for BR device count before initiating role
switch to avoid continuous loop of role switches.

Cherry-picked from: https://partner-android-review.googlesource.com/#/c/376058/

Change-Id: I70e4041a71ba965f1f9e25729c3cfd20ae03d6b4
Bug: 23290136
diff --git a/bta/dm/bta_dm_act.c b/bta/dm/bta_dm_act.c
index eb49637..5fbfb2e 100644
--- a/bta/dm/bta_dm_act.c
+++ b/bta/dm/bta_dm_act.c
@@ -3680,7 +3680,7 @@
                 }
 
                 if((bta_dm_cb.device_list.peer_device[i].pref_role == BTA_MASTER_ROLE_ONLY)
-                    || (bta_dm_cb.device_list.count > 1))
+                    || (br_count > 1))
                 {
 
                 /* Initiating immediate role switch with certain remote devices