[clang] [clang][RISCV] Extend intrinsic size check variable from 16 -> 32 bits. NFC (PR #111481)

[Craig Topper via cfe-commits]

topperc wrote:

Does the number intrinsics vary with the number of extensions enabled? Maybe we don't have a test with all extensions?

https://github.com/llvm/llvm-project/pull/111481