rtlwifi: Fix memory leak when firmware request fails

commit f2764f61 upstream.

This patch will fix memory leak when firmware request fails

Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Acked-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Cc: Sven Joachim <svenjoac@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>