Fix pwm-related build failure

Commit 076762aa is adding a macro whis is
calling imx_add_mxc_pwm() but gives it 2 parameters while it's taking only
one parameters.

Signed-off-by: Arnaud Patard <arnaud.patard@rtp-net.org>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>