staging: rtl8712: Replace function r8712_init_mlme_priv

Delete r8712_init_mlme_priv as it does nothing except call
_init_mlme_priv, and rename _init_mlme_priv to
r8712_init_mlme_priv.
Change the type of the new r8712_init_mlme_priv (formerly _init_mlme_priv)
to (non-static) int, from static sint.

Signed-off-by: Nishka Dasgupta <nishkadg.linux@gmail.com>
Reviewed-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>