spi: img-spfi: check for timeout error before proceeding

Calling spfi_wait_all_done is not required if the transfer has timed
out before all data is transferred.

spfi_wait_all_done polls for Alldone interrupt which is triggered to
mark the transfer as complete and to indicate it is now safe to issue
a new transfer.

Fixes: 8c2c8c03 ("spi: img-spfi: Control CS lines with GPIO")
Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com>
Reviewed-by: Andrew Bresticker <abrestic@chromium.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org