[GlobalISel] GISelKnownBits: forward unused depth parameter

Actually pass along the depth parameter of getKnownBits to computeKnownBitsImpl.

Reviewed By: aemerson

Differential Revision: https://reviews.llvm.org/D159321

Author: tobias-stadler

llvm/lib/CodeGen/GlobalISel/GISelKnownBits.cpp

@@ -74,7 +74,7 @@ KnownBits GISelKnownBits::getKnownBits(Register R, const APInt &DemandedElts,
   assert(ComputeKnownBitsCache.empty() && "Cache should have been cleared");
 
   KnownBits Known;
-  computeKnownBitsImpl(R, Known, DemandedElts);
+  computeKnownBitsImpl(R, Known, DemandedElts, Depth);
   ComputeKnownBitsCache.clear();
   return Known;
 }