[ARM] pxa/cm-x300: add PWM backlight support

Signed-off-by: Igor Grinberg <grinberg@compulab.co.il>
Signed-off-by: Mike Rapoport <mike@compulab.co.il>
Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
diff --git a/arch/arm/mach-pxa/Kconfig b/arch/arm/mach-pxa/Kconfig
index 20e645a..d89c6ad 100644
--- a/arch/arm/mach-pxa/Kconfig
+++ b/arch/arm/mach-pxa/Kconfig
@@ -226,6 +226,7 @@
 	select PXA3xx
 	select CPU_PXA300
 	select CPU_PXA310
+	select HAVE_PWM
 
 config MACH_COLIBRI320
 	bool "Toradex Colibri PXA320"