staging: r8822be: Simplify deinit_priv()

Now that the extraneous debugging code is removed, routine deinit_priv()
clearly contains code that serves no useful purpose.

A null test before a call to kfree() and a spurious cast are also removed.

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Ping-Ke Shih <pkshih@realtek.com>
Cc: Yan-Hsuan Chuang <yhchuang@realtek.com>
Cc: Birming Chiu <birming@realtek.com>
Cc: Shaofu <shaofu@realtek.com>
Cc: Steven Ting <steventing@realtek.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>