docs: checkpatch: add UNNECESSARY/UNSPECIFIED_INT and UNNECESSARY_ELSE

      return bar;

  **UNNECESSARY_INT**

    int used after short, long and long long is unnecessary. So remove it.

  **UNSPECIFIED_INT**

    Kernel style prefers "unsigned int <foo>" over "unsigned <foo>" and

    "signed int <foo>" over "signed <foo>".

Permissions

-----------

  **TYPO_SPELLING**

    Some words may have been misspelled.  Consider reviewing them.

  **UNNECESSARY_ELSE**

    Using an else statement just after a return or a break statement is

    unnecassary. For example::

      for (i = 0; i < 100; i++) {

              int foo = bar();

              if (foo < 1)

                      break;

              else

                      usleep(1);

      }

    is generally better written as::

      for (i = 0; i < 100; i++) {

              int foo = bar();

              if (foo < 1)

                      break;

              usleep(1);

      }

    So remove the else statement. But suppose if a if-else statement each

    with a single return statement, like::

      if (foo)

              return bar;

      else

              return baz;

    then by removing the else statement::

      if (foo)

              return bar;

      return baz;

    their is no significant increase in the readability and one can argue

    that the first form is more readable because of indentation, so for

    such cases do not convert the existing code from first form to second

    form or vice-versa.