Fix zero-extending displacement on win_x86_x64 JIT (#117945)

* treat displacement as signed value

Author: max-charlamb

src/coreclr/jit/hwintrinsiccodegenxarch.cpp

@@ -2014,8 +2014,8 @@ void CodeGen::genBaseIntrinsic(GenTreeHWIntrinsic* node, insOpts instOptions)
             unsigned simdInitTempVarNum = compiler->lvaSIMDInitTempVarNum;
             noway_assert(simdInitTempVarNum != BAD_VAR_NUM);
 
-            bool     isEBPbased;
-            unsigned offs = compiler->lvaFrameAddress(simdInitTempVarNum, &isEBPbased);
+            bool isEBPbased;
+            int  offs = compiler->lvaFrameAddress(simdInitTempVarNum, &isEBPbased);
 
 #if !FEATURE_FIXED_OUT_ARGS
             if (!isEBPbased)
@@ -2183,8 +2183,8 @@ void CodeGen::genBaseIntrinsic(GenTreeHWIntrinsic* node, insOpts instOptions)
                 unsigned simdInitTempVarNum = compiler->lvaSIMDInitTempVarNum;
                 noway_assert(simdInitTempVarNum != BAD_VAR_NUM);
 
-                bool     isEBPbased;
-                unsigned offs = compiler->lvaFrameAddress(simdInitTempVarNum, &isEBPbased);
+                bool isEBPbased;
+                int  offs = compiler->lvaFrameAddress(simdInitTempVarNum, &isEBPbased);
 
 #if !FEATURE_FIXED_OUT_ARGS
                 if (!isEBPbased)