CONFIG_SPI_PXA2XX_MASTER was used were it was surely meant to use
CONFIG_SPI_PXA2XX_MODULE. Use the IS_ENABLED() macro here, as it guards
against typos like this one.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Acked-by: Haojian Zhuang <haojian.zhuang@linaro.org>