[ARM] pxa: build pwm.c according to HAVE_PWM instead of PXA_PWM

The PXA_PWM config option is really redundant since the introduction
of HAVE_PWM, replace that with HAVE_PWM to avoid confusion.
Signed-off-by: Eric Miao <eric.miao@marvell.com>

arch/arm/mach-pxa/Kconfig

@@ -505,12 +505,6 @@ config PXA_SSP
 	help
 	  Enable support for PXA2xx SSP ports
 
-config PXA_PWM
-	tristate
-	default BACKLIGHT_PWM
-	help
-	  Enable support for PXA2xx/PXA3xx PWM controllers
-
 config TOSA_BT
 	tristate "Control the state of built-in bluetooth chip on Sharp SL-6000"
 	depends on MACH_TOSA

arch/arm/mach-pxa/Makefile

@@ -15,7 +15,7 @@ endif
 
 # Generic drivers that other drivers may depend upon
 obj-$(CONFIG_PXA_SSP)		+= ssp.o
-obj-$(CONFIG_PXA_PWM)		+= pwm.o
+obj-$(CONFIG_HAVE_PWM)		+= pwm.o
 
 # SoC-specific code
 obj-$(CONFIG_PXA25x)		+= mfp-pxa2xx.o pxa2xx.o pxa25x.o