Ensure MINIMUM_PULSE is always 0 in DEDGE mode

This ensures delays are always properly elided without having to check
for DEDGE all over the place.

Firmware/stepper.cpp

@@ -83,6 +83,7 @@ uint16_t SP_min = 0x21FF;
 #endif
 
 #ifdef TMC2130_DEDGE_STEPPING
+static_assert(TMC2130_MINIMUM_PULSE == 0, "DEDGE requires/implies TMC2130_MINIMUM_PULSE == 0");
 #define STEP_NC_HI(axis) TOGGLE(_STEP_PIN_##axis)
 #define STEP_NC_LO(axis) //NOP
 #else