cosmetic: update doc/README.scrapyard

- Add 'p1023rds' to the list since commit d0bc5140 dropped
   the board support but missed to update this file
 - Fill the Commit and Removed Date fields for boards removed
   by earlier commits
 - Move 'incaip' to keep the list sorted in reverse
   chronological order
 - Describe the soring rule in the comment block:
   "The list should be sorted in reverse chronological order."
 - Fix typos in the comment block

Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>