components/bt: Move function in interrupt into IRAM

1. Move function in interrupt into IRAM
2. Delete unused code, saving 240B DRAM and some code size

diff --git a/components/bt/lib b/components/bt/lib
index 93c0b8303a9ab46d1248d28896b7a45fab559c5c..50828eae8345f519a533199c09133966add936f6 160000 (submodule)
--- a/components/bt/lib
+++ b/components/bt/lib
@@ -1 +1 @@
-Subproject commit 93c0b8303a9ab46d1248d28896b7a45fab559c5c
+Subproject commit 50828eae8345f519a533199c09133966add936f6