net: appletalk: Drop aarp_send_probe_phase1()

aarp_send_probe_phase1() used to work by calling ndo_do_ioctl of
appletalk drivers ltpc or cops, but these two drivers have been removed
since the following commits:
commit 03dcb90d ("net: appletalk: remove Apple/Farallon LocalTalk PC
support")
commit 00f3696f ("net: appletalk: remove cops support")

Thus aarp_send_probe_phase1() no longer works, so drop it. (found by
code inspection)

Signed-off-by: 谢致邦 (XIE Zhibang) <Yeking@Red54.com>
Signed-off-by: David S. Miller <davem@davemloft.net>