ARM: imx/mx25: fix (again) spi device registration typo

This typo was fixed in 46e3f307 (mx25: fix spi device registration typo), but a
the merge at 0e44e059 (Merge commit 'v2.6.37-rc4' into imx-for-2.6.38) resolved
the merge conflict wrongly.

Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>