staging: r8188eu: convert rtw_p2p_get_peer_devaddr to return void

rtw_p2p_get_peer_devaddr always returns 0 and it's return value is not
used. Convert it to return void.

Suggested-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Abdun Nihaal <abdun.nihaal@gmail.com>
Link: https://lore.kernel.org/r/cc077a7d11e4bda521294499c42164db7358b2e1.1643466748.git.abdun.nihaal@gmail.com


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