Everywhere: Switch from (void) to [[maybe_unused]] (#4473)

Problem:
- `(void)` simply casts the expression to void. This is understood to
  indicate that it is ignored, but this is really a compiler trick to
  get the compiler to not generate a warning.

Solution:
- Use the `[[maybe_unused]]` attribute to indicate the value is unused.

Note:
- Functions taking a `(void)` argument list have also been changed to
  `()` because this is not needed and shows up in the same grep
  command.

1 files changed, 1 insertions, 1 deletions

diff --git a/Kernel/Interrupts/APIC.cpp b/Kernel/Interrupts/APIC.cpp
index 22709f2956..103fd1db8a 100644
--- a/Kernel/Interrupts/APIC.cpp
+++ b/Kernel/Interrupts/APIC.cpp
@@ -210,7 +210,7 @@ void APIC::write_icr(const ICRReg& icr)
 #define APIC_LVT_TRIGGER_LEVEL (1 << 14)
 #define APIC_LVT(iv, dm) (((iv)&0xff) | (((dm)&0x7) << 8))
 
-extern "C" void apic_ap_start(void);
+extern "C" void apic_ap_start();
 extern "C" u16 apic_ap_start_size;
 extern "C" u32 ap_cpu_init_stacks;
 extern "C" u32 ap_cpu_init_processor_info_array;