rialto: Remove activate_kernel_pgt function

Minor cleanup. Just call the activate() function from init_kernel_pgt.

Test: atest rialto_test
Change-Id: Ibc5762d91c06632da5d64e4c4ecddb3b61f8008b
diff --git a/rialto/src/main.rs b/rialto/src/main.rs
index e95be30..8710c49 100644
--- a/rialto/src/main.rs
+++ b/rialto/src/main.rs
@@ -102,13 +102,9 @@
     pgt.map_range(&reg_rodata, PROT_RO)?;
     pgt.map_range(&reg_data, PROT_RW)?;
 
-    info!("Finished preparing kernel page table.");
-    Ok(())
-}
-
-fn activate_kernel_pgt(pgt: &mut IdMap) {
     pgt.activate();
     info!("Activated kernel page table.");
+    Ok(())
 }
 
 /// Entry point for Rialto.
@@ -120,7 +116,6 @@
 
     let mut pgt = IdMap::new(PT_ASID, PT_ROOT_LEVEL);
     init_kernel_pgt(&mut pgt).unwrap();
-    activate_kernel_pgt(&mut pgt);
 }
 
 extern "C" {