Bundle proc_bootconfig permission into read_fstab

fs_mgr::ReadDefaultFstab calls fs_mgr:ReadFstabFromDt() which eventually
calls fs_mgr_get_boot_config_from_bootconfig_source to read boot config.
Therefore bundle permission to read proc_bootconfig. This resolves some
selinux denials for update_engine

Test: th
Change-Id: Ia8bd94eb33a38ccd939577b54910645fec4ccda8
diff --git a/microdroid/system/public/te_macros b/microdroid/system/public/te_macros
index 9e73292..1a7aaa4 100644
--- a/microdroid/system/public/te_macros
+++ b/microdroid/system/public/te_macros
@@ -985,4 +985,5 @@
 define(`read_fstab', `
   allow $1 { metadata_file gsi_metadata_file_type }:dir search;
   allow $1 gsi_public_metadata_file:file r_file_perms;
+  allow $1 proc_bootconfig:file r_file_perms;
 ')
diff --git a/public/te_macros b/public/te_macros
index 4cd7e53..c112cc1 100644
--- a/public/te_macros
+++ b/public/te_macros
@@ -1019,4 +1019,5 @@
 define(`read_fstab', `
   allow $1 { metadata_file gsi_metadata_file_type }:dir search;
   allow $1 gsi_public_metadata_file:file r_file_perms;
+  allow $1 proc_bootconfig:file r_file_perms;
 ')