misc: Fix a few accidental transitive includes.

Some files depend on definitions from files that they weren't including
themselves. They were working accidentally by getting those definitions
transitively through other, unrelated headers.

Change-Id: I50c919a4eb6c4484d4ee6b7f4fe02f075132964d
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/36282
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

src/arch/riscv/pagetable.hh

@@ -31,6 +31,7 @@
 #ifndef __ARCH_RISCV_PAGETABLE_H__
 #define __ARCH_RISCV_PAGETABLE_H__
 
+#include "base/bitunion.hh"
 #include "base/logging.hh"
 #include "base/trie.hh"
 #include "base/types.hh"

src/arch/riscv/registers.hh

@@ -53,6 +53,7 @@
 #include "arch/generic/vec_pred_reg.hh"
 #include "arch/generic/vec_reg.hh"
 #include "arch/riscv/generated/max_inst_regs.hh"
+#include "base/bitunion.hh"
 #include "base/types.hh"
 
 namespace RiscvISA {