chore: remove shortcut instance that is no longer needed (leanprover-community#38284)

Author: jcommelin

Mathlib/Analysis/Fourier/AddCircleMulti.lean

@@ -216,11 +216,6 @@ theorem coeFn_mFourierLp (p : ℝ≥0∞) [Fact (1 ≤ p)] (n : d → ℤ) :
     mFourierLp p n =ᵐ[volume] mFourier n :=
   ContinuousMap.coeFn_toLp volume (mFourier n)
 
--- shortcut instance: avoids `synthInstance.maxHeartbeats` issue in `span_mFourierLp_closure_eq_top`
-instance {p : ℝ≥0∞} [Fact (1 ≤ p)] :
-    ContinuousSMul ℂ (Lp ℂ p (volume : Measure (UnitAddTorus d))) :=
-  inferInstance
-
 /-- For each `1 ≤ p < ∞`, the linear span of the monomials `mFourier n` is dense in the `Lᵖ` space
 of functions on `UnitAddTorus d`. -/
 theorem span_mFourierLp_closure_eq_top {p : ℝ≥0∞} [Fact (1 ≤ p)] (hp : p ≠ ∞) :