ARM i.MX23/28: do not use complicated macros if not necessary

Get rid of ## preprocessor construct where it only makes the
code harder to read.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Shawn Guo <shawn.guo@freescale.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>