Kernel: Refactor storage stack with u64 as file operations offset

Author: https://github.com/boricj
Commit: b05b4d4b24
Pull-request: https://github.com/SerenityOS/serenity/pull/5766
Reviewed-by: https://github.com/supercomputer7

Kernel/Devices/NullDevice.cpp

@@ -56,12 +56,12 @@ bool NullDevice::can_read(const FileDescription&, size_t) const
     return true;
 }
 
-KResultOr<size_t> NullDevice::read(FileDescription&, size_t, UserOrKernelBuffer&, size_t)
+KResultOr<size_t> NullDevice::read(FileDescription&, u64, UserOrKernelBuffer&, size_t)
 {
     return 0;
 }
 
-KResultOr<size_t> NullDevice::write(FileDescription&, size_t, const UserOrKernelBuffer&, size_t buffer_size)
+KResultOr<size_t> NullDevice::write(FileDescription&, u64, const UserOrKernelBuffer&, size_t buffer_size)
 {
     return min(static_cast<size_t>(PAGE_SIZE), buffer_size);
 }