[MLIR][GPUToSPIRV] Passing gpu module name to SPIR-V module
This patch allows to pass the gpu module name to SPIR-V
module during conversion. This has many benefits as we can lookup
converted to SPIR-V kernel in the symbol table.
In order to avoid symbol conflicts, "__spv__" is added to the
gpu module name to form the new one.
Reviewed By: mravishankar
Differential Revision: https://reviews.llvm.org/D86384