Revert "spi: Merge spi_controller.{slave,target}_abort()"

This reverts commit 2f5e8322 which is
commit 6c6871cd upstream.

It breaks the Android kernel abi and can be brought back in the future
in an abi-safe way if it is really needed.

Bug: 161946584
Change-Id: Ie74bf735e9102ae636f40b30ceff41e097f667e4
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>