Fix RISCV build after r318352

[mgrang]

Thanks! LGTM.

[asb]

Thanks, and do feel free to directly commit build fixes like this if you have commit access without pre-commit review.

I have a buildbot slave mostly setup for the staging buildbot (which doesn't email the committer upon failure, which is the right behaviour for an "experimental" backend). Just need to find the time to finalise the config and get it added. Once that's done it should be easier to spot these breakages.

lib/Target/RISCV/TargetInfo/RISCVTargetInfo.cpp

 
 extern "C" void LLVMInitializeRISCVTargetInfo() {
   RegisterTarget<Triple::riscv32> X(getTheRISCV32Target(), "riscv32",
-                                    "32-bit RISC-V");
+                                    "32-bit RISC-V", "RISCV");
   RegisterTarget<Triple::riscv64> Y(getTheRISCV64Target(), "riscv64",
-                                    "64-bit RISC-V");
+                                    "64-bit RISC-V", "RISCV");
 }