pwm: mediatek: Fix Kconfig description

Fix a copy/paste error that sneaked into the Kconfig description of the
Mediatek PWM driver.
Signed-off-by: Zhi Mao <zhi.mao@mediatek.com>
Acked-by: John Crispin <john@phrozen.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

drivers/pwm/Kconfig

@@ -300,7 +300,7 @@ config PWM_MEDIATEK
 	  Generic PWM framework driver for Mediatek ARM SoC.
 
 	  To compile this driver as a module, choose M here: the module
-	  will be called pwm-mxs.
+	  will be called pwm-mediatek.
 
 config PWM_MXS
 	tristate "Freescale MXS PWM support"