[MLIR] Add missing MLIRGPUDialect dep to MLIRSPIRVDialect (#84554)

This fixes the following failure when doing a clean build (in particular
no .ninja* lying around) of lib/libMLIRSPIRVDialect.a only:
```
mlir/lib/Dialect/SPIRV/IR/SPIRVDialect.cpp:17:
mlir/include/mlir/Dialect/GPU/IR/CompilationInterfaces.h:120:10: fatal error: mlir/Dialect/GPU/IR/CompilationAttrInterfaces.h.inc: No such file or directory
```