nios2: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names

nios2: ptrace: Use USER_REGSET_NOTE_TYPE() to specify regset note names

Instead of having the core code guess the note name for each regset,
use USER_REGSET_NOTE_TYPE() to pick the correct name from elf.h.

Signed-off-by: Dave Martin <Dave.Martin@arm.com>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Cc: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Akihiko Odaki <odaki@rsg.ci.i.u-tokyo.ac.jp>
Link: https://lore.kernel.org/r/20250701135616.29630-13-Dave.Martin@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>