spi: synquacer: Fix timeout handling in synquacer_spi_transfer_one()

spi: synquacer: Fix timeout handling in synquacer_spi_transfer_one()

wait_for_completion_timeout() never returns a <0 value. It returns either
on timeout or a positive value (at least 1, or number of jiffies left
till timeout)

So, fix the error handling path and return -ETIMEDOUT should a timeout
occur.

Fixes: b0823ee35cf9 ("spi: Add spi driver for Socionext SynQuacer platform")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Acked-by: Jassi Brar <jaswinder.singh@linaro.org>
Link: https://lore.kernel.org/r/c2040bf3cfa201fd8890cfab14fa5a701ffeca14.1676466072.git.christophe.jaillet@wanadoo.fr
Signed-off-by: Mark Brown <broonie@kernel.org>