libcutils: Add missing dependency on libprocessgroup_headers

cutils/sched_policy.h redirects to processgroup/sched_policy.h, but
libcutils does not export the libprocessgroup headers. So users have to
know about the hidden redirect to libprocessgroup and include a
libprocessgroup dependency in their Android.bp files in addition to
libcutils. Fix that.

Bug: 349105928
Test: m
Change-Id: I516bdf2cdeff980c1fcd18883ef8a2f0a9beb629
diff --git a/libcutils/Android.bp b/libcutils/Android.bp
index e297581..39cae1b 100644
--- a/libcutils/Android.bp
+++ b/libcutils/Android.bp
@@ -47,6 +47,8 @@
     defaults: ["libcutils_defaults"],
 
     export_include_dirs: ["include"],
+    header_libs: ["libprocessgroup_headers"],
+    export_header_lib_headers: ["libprocessgroup_headers"],
     target: {
         vendor: {
             override_export_include_dirs: ["include_outside_system"],