If devm_spi_register_master() fails in meson_spicc_probe(),
spicc->core is left undisabled. The patch fixes that.

Found by Linux Driver Verification project (linuxtesting.org).
Signed-off-by: NAlexey Khoroshilov <khoroshilov@ispras.ru>
Reviewed-by: NNeil Armstrong <narmstrong@baylibre.com>
Signed-off-by: NMark Brown <broonie@kernel.org>