Kernel: Remove i686 support

Author: https://github.com/supercomputer7
Commit: 5ff318cf3a
Pull-request: https://github.com/SerenityOS/serenity/pull/15467
Issue: https://github.com/SerenityOS/serenity/issues/15444
Reviewed-by: https://github.com/ADKaster
Reviewed-by: https://github.com/Hendiadyoin1
Reviewed-by: https://github.com/fuel-pcbox

Kernel/Syscalls/beep.cpp

@@ -5,7 +5,7 @@
  */
 
 #include <Kernel/CommandLine.h>
-#if ARCH(I386) || ARCH(X86_64)
+#if ARCH(X86_64)
 #    include <Kernel/Arch/x86/common/PCSpeaker.h>
 #endif
 #include <Kernel/Process.h>
@@ -17,7 +17,7 @@ ErrorOr<FlatPtr> Process::sys$beep()
     VERIFY_NO_PROCESS_BIG_LOCK(this);
     if (!kernel_command_line().is_pc_speaker_enabled())
         return ENODEV;
-#if ARCH(I386) || ARCH(X86_64)
+#if ARCH(X86_64)
     PCSpeaker::tone_on(440);
     auto result = Thread::current()->sleep(Time::from_nanoseconds(200'000'000));
     PCSpeaker::tone_off();