staging: rtl8712: Invert comparison to reduce indentation

Check the condition: "pdata->length < 32" first, to be able to return immediately
in case of error and then continue with the rest of the function without one
extra indentation level.

This was found using the following Coccinelle script:

@disable neg_if@
expression e,E;
statement S;
@@

*if (e)
    S
    else { return -E; }

    @disable neg_if@
    expression e,E;
    statement S;
    identifier l;
    @@

    *if
(e)
    S
    else
{ rc = -E; goto l; }

Signed-off-by: Narcisa Ana Maria Vasile <narcisaanamaria12@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>