staging: rtl8712: Drop get_recvframe_data()

As done for rtl8723bs and r8188eu, drop get_recvframe_data(), as it
introduces an impossible value (NULL) for the compiler to check code
paths against which could result in nonsensical warnings.

Cc: Larry Finger <Larry.Finger@lwfinger.net>
Cc: Florian Schilhabel <florian.c.schilhabel@googlemail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Cc: Zhansaya Bagdauletkyzy <zhansayabagdaulet@gmail.com>
Cc: Ivan Safonov <insafonov@gmail.com>
Cc: linux-staging@lists.linux.dev
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20220118193327.2822099-4-keescook@chromium.org


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>