spi: fsi: Convert to fsi bus probe mechanism

spi: fsi: Convert to fsi bus probe mechanism

The fsi bus got a dedicated probe function. Make use of that. This fixes
a runtime warning about the driver needing to be converted to the bus
probe method.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Acked-by: Mark Brown <broonie@kernel.org>
Acked-by: Eddie James <eajames@linux.ibm.com>
Link: https://patch.msgid.link/fc2a758ef00844dd5bd614a25b36a4a38355d12d.1765279318.git.u.kleine-koenig@baylibre.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>