AK+Kernel+LibELF: Remove the need for `IteratorDecision::Continue`

By constraining two implementations, the compiler will select the best
fitting one. All this will require is duplicating the implementation and
simplifying for the `void` case.

This constraining also informs both the caller and compiler by passing
the callback parameter types as part of the constraint
(e.g.: `IterationFunction<int>`).

Some `for_each` functions in LibELF only take functions which return
`void`. This is a minimal correctness check, as it removes one way for a
function to incompletely do something.

There seems to be a possible idiom where inside a lambda, a `return;` is
the same as `continue;` in a for-loop.

1 files changed, 2 insertions, 4 deletions

diff --git a/Kernel/Arch/i386/CPU.cpp b/Kernel/Arch/i386/CPU.cpp
index b33e48f659..661eb8653c 100644
--- a/Kernel/Arch/i386/CPU.cpp
+++ b/Kernel/Arch/i386/CPU.cpp
@@ -2090,12 +2090,11 @@ void Processor::smp_broadcast_message(ProcessorMessage& msg)
     VERIFY(msg.refs > 0);
     bool need_broadcast = false;
     for_each(
-        [&](Processor& proc) -> IterationDecision {
+        [&](Processor& proc) {
             if (&proc != &cur_proc) {
                 if (proc.smp_queue_message(msg))
                     need_broadcast = true;
             }
-            return IterationDecision::Continue;
         });
 
     // Now trigger an IPI on all other APs (unless all targets already had messages queued)
@@ -2215,9 +2214,8 @@ void Processor::smp_broadcast_halt()
     // We don't want to use a message, because this could have been triggered
     // by being out of memory and we might not be able to get a message
     for_each(
-        [&](Processor& proc) -> IterationDecision {
+        [&](Processor& proc) {
             proc.m_halt_requested.store(true, AK::MemoryOrder::memory_order_release);
-            return IterationDecision::Continue;
         });
 
     // Now trigger an IPI on all other APs