Frequency check: Only check range

Signed-off-by: Chris Fiege <chris@tinyhost.de>

sa868/__init__.py

@@ -16,10 +16,7 @@ class SA868(object):
 
     def _check_freq_range(self, freq):
         if (freq >= 400 and freq <= 480) or (freq >= 134 and freq <=174):
-            if (freq * 1000) % 12.5 == 0:
-                return True
-            else:
-                raise Exception("Frequency is not a multiple of 12.5kHz")
+            return True
         else:
             raise Exception("Frequency out of bounds")