spi: img-spfi: fix kbuild test robot warning

drivers/spi/spi-img-spfi.c: In function 'img_spfi_setup':
drivers/spi/spi-img-spfi.c:446: warning: 'ret' may be used
uninitialized in this function.

Fixes: commit b03ba9e314c1 ("spi: img-spfi: fix multiple calls to request gpio")
Signed-off-by: Sifan Naeem <sifan.naeem@imgtec.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org

drivers/spi/spi-img-spfi.c

@@ -443,7 +443,7 @@ static int img_spfi_unprepare(struct spi_master *master,
 
 static int img_spfi_setup(struct spi_device *spi)
 {
-	int ret;
+	int ret = -EINVAL;
 	struct img_spfi_device_data *spfi_data = spi_get_ctldata(spi);
 
 	if (!spfi_data) {