spi: bcm2835aux: Call the dedicated transfer completion function.

spi_finalize_current_transfer currently only calls "complete", so no
functional change is expected.

Signed-off-by: Vincent Pelletier <plr.vincent@gmail.com>
Link: https://lore.kernel.org/r/2636096a3b40febf680f9fff33944a5480561df9.1610062884.git.plr.vincent@gmail.com


Signed-off-by: Mark Brown <broonie@kernel.org>