misc: atmel_pwm: only build for supported platforms

There is architecture code in mach-at91 that depends on the
CONFIG_ATMEL_PWM symbol in order to call the soc-specific
at91_add_device_pwm function. While all of this is about code
that will be removed in the future, using DT probing and
the PWM framework, we currently get a build failure:

arch/arm/mach-at91/built-in.o: In function `at91_pwm_leds':
arch/arm/mach-at91/leds.c:88: undefined reference to `at91_add_device_pwm'

This patch ensures we only try to build this driver on
platforms on which it will build and work.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/misc/Kconfig

@@ -53,7 +53,8 @@ config AD525X_DPOT_SPI
 
 config ATMEL_PWM
 	tristate "Atmel AT32/AT91 PWM support"
-	depends on HAVE_CLK && (AVR32 || ARCH_AT91 || COMPILE_TEST)
+	depends on HAVE_CLK
+	depends on AVR32 || AT91SAM9263 || AT91SAM9RL || AT91SAM9G45
 	help
 	  This option enables device driver support for the PWM channels
 	  on certain Atmel processors.  Pulse Width Modulation is used for