spi: davinci: Use of_match_ptr at appropriate place

It's pointless to use of_match_ptr within CONFIG_OF guard.
Use of_match_ptr around davinci_spi_of_match when setting .of_match_table.

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Mark Brown <broonie@linaro.org>