Remove flag save_peer_csrk_after_ltk_gen

This is a backport of ag/32978033, required to complete security fix for b#288144143 without regressions on 25Q2-staging.

Test: mmm packages/modules/Bluetooth
Flag: EXEMPT removing save_peer_csrk_after_ltk_gen
Bug: 288144143
(cherry picked from commit 11acef3e45abeb5aa366e8176756f9ccf5e8727a)
Cherrypick-From: https://googleplex-android-review.googlesource.com/q/commit:39f03f3f8f9c6e92e8cfe384db1025fb573ab23a
Merged-In: Id260fa7ef7a982e93649b063378773c69c23e91d
Change-Id: Id260fa7ef7a982e93649b063378773c69c23e91d

flags/pairing.aconfig

diff --git a/flags/pairing.aconfig b/flags/pairing.aconfig
index aff4cbe..f5b1f3a 100644
--- a/flags/pairing.aconfig
+++ b/flags/pairing.aconfig
@@ -72,16 +72,6 @@
 }
 
 flag {
-    name: "save_peer_csrk_after_ltk_gen"
-    namespace: "bluetooth"
-    description: "save peer csrk after ltk generated so that right security level is marked as part of peer csrk"
-    bug: "365567905"
-    metadata {
-        purpose: PURPOSE_BUGFIX
-    }
-}
-
-flag {
     name: "wait_for_lea_disc_on_le_acl_stat"
     namespace: "bluetooth"
     description: "Check for LE ACL status before waiting on LEA discovery"

system/stack/smp/smp_act.cc

diff --git a/system/stack/smp/smp_act.cc b/system/stack/smp/smp_act.cc
index cfc696a..b9faeea 100644
--- a/system/stack/smp/smp_act.cc
+++ b/system/stack/smp/smp_act.cc
@@ -1099,9 +1099,7 @@
 
   smp_update_key_mask(p_cb, SMP_SEC_KEY_TYPE_CSRK, true);
 
-  if (com::android::bluetooth::flags::save_peer_csrk_after_ltk_gen()) {
-    smp_key_distribution_by_transport(p_cb, NULL);
-  }
+  smp_key_distribution_by_transport(p_cb, NULL);
 
   /* save CSRK to security record */
   tBTM_LE_KEY_VALUE le_key = {
@@ -1120,10 +1118,6 @@
   if ((p_cb->peer_auth_req & SMP_AUTH_BOND) && (p_cb->loc_auth_req & SMP_AUTH_BOND)) {
     btm_sec_save_le_key(p_cb->pairing_bda, BTM_LE_KEY_PCSRK, &le_key, true);
   }
-
-  if (!com::android::bluetooth::flags::save_peer_csrk_after_ltk_gen()) {
-    smp_key_distribution_by_transport(p_cb, NULL);
-  }
 }
 
 /*******************************************************************************