compiling the i.MX pwm driver produces the following warning:
|drivers/pwm/pwm-imx.c: In function 'imx_pwm_probe':
|drivers/pwm/pwm-imx.c:281:7: warning: assignment discards qualifiers from pointer target type

Apply a 'const' attribute to the affected variable declaration.
Signed-off-by: NLothar Waßmann <LW@KARO-electronics.de>
Acked-by: NSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: NThierry Reding <thierry.reding@avionic-design.de>