Fix checking variable frequency

Author: tekktrik

adafruit_motor/stepper.py

@@ -113,15 +113,13 @@ def __init__(
             # set a safe pwm freq for each output
             self._coil = (ain2, bin1, ain1, bin2)
             for i in range(4):
-                if (
-                    self._coil[i].frequency < 1500
-                    and not self._coil[i].variable_frequency
-                ):
-                    raise ValueError(
-                        "PWMOut outputs must either be set to at least "
-                        "1500 Hz or allow variable frequency."
-                    )
-                self._coil[i].frequency = 2000
+                if self._coil[i].frequency < 1500:
+                    if not self._coil[i].variable_frequency:
+                        raise ValueError(
+                            "PWMOut outputs must either be set to at least "
+                            "1500 Hz or allow variable frequency."
+                        )
+                    self._coil[i].frequency = 2000
             if microsteps < 2:
                 raise ValueError("Microsteps must be at least 2")
             if microsteps % 2 == 1: