pwm: mxs: Check the return value from stmp_reset_block()
stmp_reset_block() may fail, so let's check its return value and
propagate it in the case of error.
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>