Kernel/aarch64: Change RPi::Framebuffer::PixelOrder to BGR

This is what the WindowServer expects. Confusingly the pixel format for
MULTIBOOT_FRAMEBUFFER_TYPE_RGB is actually BGRx8888.

Kernel/Arch/aarch64/RPi/Framebuffer.cpp

@@ -48,7 +48,7 @@ Framebuffer::Framebuffer()
  // message_queue.set_virtual_offset.y = 0;
 
  message_queue.set_depth.depth_bits = 32;
- message_queue.set_pixel_order.pixel_order = FramebufferSetPixelOrderMboxMessage::PixelOrder::RGB;
+ message_queue.set_pixel_order.pixel_order = FramebufferSetPixelOrderMboxMessage::PixelOrder::BGR;
  message_queue.allocate_buffer.alignment = 4096;
 
  if (!Mailbox::the().send_queue(&message_queue, sizeof(message_queue))) {
@@ -127,7 +127,8 @@ void Framebuffer::initialize()
  multiboot_framebuffer_height = framebuffer.height();
  multiboot_framebuffer_pitch = framebuffer.pitch();
 
- VERIFY(framebuffer.pixel_order() == PixelOrder::RGB);
+ // NOTE: The required pixel format for MULTIBOOT_FRAMEBUFFER_TYPE_RGB is actually BGRx8888.
+ VERIFY(framebuffer.pixel_order() == PixelOrder::BGR);
  multiboot_framebuffer_type = MULTIBOOT_FRAMEBUFFER_TYPE_RGB;
  }
 }