Kernel: Use Processor::wait_check in loops waiting for HW to respond

This gives the processor the hint that it is in a hot loop and allows us
to do other work in between

Kernel/Arch/aarch64/RPi/Mailbox.cpp

@@ -64,13 +64,13 @@ static void wait_until_we_can_write(MMIO& mmio)
     // Since nothing else writes to the mailbox, this wait is mostly cargo-culted.
     // Most baremetal tutorials on the internet query MBOX_READ_STATUS here, which I think is incorrect and only works because this wait really isn't needed.
     while (mmio.read(MBOX_WRITE_STATUS) & MBOX_FULL)
-        ;
+        Processor::wait_check();
 }
 
 static void wait_for_reply(MMIO& mmio)
 {
     while (mmio.read(MBOX_READ_STATUS) & MBOX_EMPTY)
-        ;
+        Processor::wait_check();
 }
 
 bool Mailbox::send_queue(void* queue, u32 queue_size) const

Kernel/Arch/aarch64/RPi/MiniUART.cpp

@@ -114,7 +114,7 @@ ErrorOr<size_t> MiniUART::write(Kernel::OpenFileDescription& description, u64, K
 void MiniUART::put_char(u8 ch)
 {
     while ((m_registers->line_status & TransmitterEmpty) == 0)
-        ;
+        Processor::wait_check();
 
     if (ch == '\n' && !m_last_put_char_was_carriage_return)
         m_registers->io_data = '\r';

Kernel/Arch/aarch64/RPi/UART.cpp

@@ -160,13 +160,13 @@ void UART::set_baud_rate(int baud_rate, int uart_frequency_in_hz)
 void UART::wait_until_we_can_send()
 {
     while (m_registers->flag & TransmitFifoFull)
-        ;
+        Processor::wait_check();
 }
 
 void UART::wait_until_we_can_receive()
 {
     while (m_registers->flag & ReceiveFifoEmpty)
-        ;
+        Processor::wait_check();
 }
 
 }

Kernel/Arch/x86_64/DebugOutput.cpp

@@ -7,6 +7,7 @@
 #include <Kernel/Arch/DebugOutput.h>
 #include <Kernel/Arch/x86_64/BochsDebugOutput.h>
 #include <Kernel/Arch/x86_64/IO.h>
+#include <Kernel/Arch/x86_64/Processor.h>
 
 namespace Kernel {
 
@@ -35,7 +36,7 @@ void debug_output(char ch)
     }
 
     while ((IO::in8(serial_com1_io_port + 5) & 0x20) == 0)
-        ;
+        Processor::wait_check();
 
     if (ch == '\n' && !was_cr)
         IO::out8(serial_com1_io_port, '\r');

Kernel/Arch/x86_64/Time/APICTimer.cpp

@@ -91,7 +91,7 @@ UNMAP_AFTER_INIT bool APICTimer::calibrate(HardwareTimerBase& calibration_source
     sti();
     // Loop for about 100 ms
     while (state.calibration_ticks.load() <= state.ticks_in_100ms)
-        ;
+        Processor::wait_check();
     cli();
 
     // Restore timer callbacks