wifi: ti: remove obsolete lines in the Makefile

Commit 06463f6e ("wifi: wl1251: drop support for platform data")
removes TI WiLink platform data, but leaves some dead lines in the
Makefile.

Remove these obsolete lines in the Makefile.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221209095937.17773-1-lukas.bulwahn@gmail.com