[mlir][Bazel] Add missing dependency.

Author: akuegel

utils/bazel/llvm-project-overlay/mlir/BUILD.bazel

@@ -3705,6 +3705,7 @@ cc_library(
         ":GPUToSPIRV",
         ":GPUToVulkanTransforms",
         ":IndexToLLVM",
+        ":IndexToSPIRV",
         ":LinalgToStandard",
         ":MathToFuncs",
         ":MathToLLVM",
@@ -5989,7 +5990,6 @@ cc_library(
     ],
 )
 
-
 cc_library(
     name = "NVVMToLLVM",
     srcs = glob(["lib/Conversion/NVVMToLLVM/NVVMToLLVM.cpp"]),