Set speed offset

Added toggle to apply an offset to the set speed.

Co-Authored-By: Tim Wilson <7284371+twilsonco@users.noreply.github.com>

selfdrive/controls/lib/drive_helpers.py

@@ -114,6 +114,12 @@ class VCruiseHelper:
     else:
       self.v_cruise_kph += v_cruise_delta * CRUISE_INTERVAL_SIGN[button_type]
 
+    # Apply offset
+    v_cruise_offset = (frogpilot_variables.set_speed_offset * CRUISE_INTERVAL_SIGN[button_type]) if long_press else 0
+    if v_cruise_offset < 0:
+      v_cruise_offset = frogpilot_variables.set_speed_offset - v_cruise_delta
+    self.v_cruise_kph += v_cruise_offset
+
     # If set is pressed while overriding, clip cruise speed to minimum of vEgo
     if CS.gasPressed and button_type in (ButtonType.decelCruise, ButtonType.setCruise):
       self.v_cruise_kph = max(self.v_cruise_kph, CS.vEgo * CV.MS_TO_KPH)