ARM: imx: pwm: Add support for MX53

Instead of adding the check for MX53 CPU type, use the negative logic and let
PWM to be configured for MX53 as well.

Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
diff --git a/arch/arm/plat-mxc/pwm.c b/arch/arm/plat-mxc/pwm.c
index 761c3c9..42d74ea 100644
--- a/arch/arm/plat-mxc/pwm.c
+++ b/arch/arm/plat-mxc/pwm.c
@@ -57,7 +57,7 @@
 	if (pwm == NULL || period_ns == 0 || duty_ns > period_ns)
 		return -EINVAL;
 
-	if (cpu_is_mx27() || cpu_is_mx3() || cpu_is_mx25() || cpu_is_mx51()) {
+	if (!(cpu_is_mx1() || cpu_is_mx21())) {
 		unsigned long long c;
 		unsigned long period_cycles, duty_cycles, prescale;
 		u32 cr;