[ARM] MXC: add pwm driver for i.MX SoCs

This driver has been tested on MX27/MX31. It should work on MX1/MX1
aswell, but the actual setting of the PWM is missing so far.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/plat-mxc/Kconfig b/arch/arm/plat-mxc/Kconfig
index 10f65bf..71c3c84 100644
--- a/arch/arm/plat-mxc/Kconfig
+++ b/arch/arm/plat-mxc/Kconfig
@@ -44,4 +44,10 @@
 	  requirements for timing.
 	  Say N here, unless you have a specialized requirement.
 
+config MXC_PWM
+	tristate "Enable PWM driver"
+	depends on ARCH_MXC
+	help
+	  Enable support for the i.MX PWM controller(s).
+
 endif