esp32: update libraries

This removes librtc_{clk,pm}.a and updates librtc.a to use the new
functions defined in ESP-IDF source code.

diff --git a/components/esp32/lib b/components/esp32/lib
index ae20d8efce9c46dea9dc949b542d8dfaa3ea136c..8ac3a6e76d11e3fec6bbbee5ca7d9b3a38435e4d 160000 (submodule)
--- a/components/esp32/lib
+++ b/components/esp32/lib
@@ -1 +1 @@
-Subproject commit ae20d8efce9c46dea9dc949b542d8dfaa3ea136c
+Subproject commit 8ac3a6e76d11e3fec6bbbee5ca7d9b3a38435e4d