package/readline: bump to version 8.0

- Remove first patch (already in version) and so remove
  READLINE_AUTOCONF as configure.ac is not patched anymore
- Use the new --disable-install-examples option and remove
  READLINE_PURGE_EXAMPLES
- Remove READLINE_INSTALL_PC_FILE as readline.pc is installed since:
  http://git.savannah.gnu.org/cgit/readline.git/commit/Makefile.in?id=8e6ccd0373d77b86ed37a9a7d232ccfea3d6670c


- Remove READLINE_INSTALL_FIXUPS_SHARED (libraries are installed with
  correct rights)
- Add hash for license file

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>