ARM: dts: imx25-pinfunc: remove duplicate definition

This was introduced in commit 18e2b504

 ("ARM: dts: imx25-pinfunc:
more defines").

Signed-off-by: Uwe Kleine-König <uwe@kleine-koenig.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>