spi: davinci: Fix compilation warning.

If CONFIG_OF is disable, it'll through compilation warning.

drivers/spi/spi-davinci.c: In function ‘spi_davinci_get_pdata’:
drivers/spi/spi-davinci.c:880:2: warning: return makes pointer from integer without a cast [enabled by default]
  return -ENODEV;

drivers/spi/spi-davinci.c: In function ‘davinci_spi_probe’:
drivers/spi/spi-davinci.c:919:7: warning: assignment makes integer from pointer without a cast [enabled by default]
   ret = spi_davinci_get_pdata(pdev, dspi);

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>

Changes in v2:
             Add fix for both the warning.
Changes in v1:
             It has fix for first warning.
Signed-off-by: Mark Brown <broonie@kernel.org>