ARM i.MX27 eukrea: Fix compilation

Currently compilation breaks for the eukrea mbimx27 baseboard
when CONFIG_SPI_IMX is selected and CONFIG_TOUCHSCREEN_ADS7846
is not selected. Fix this by removing the ifdefs altogether.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Cc: Eric Benard <eric@eukrea.com>