[llvm] [RISCV] Use hasStdExtCOrZca instead of hasStdExtC in estimateFunctionSizeInBytes. (PR #80905)

[Philip Reames via llvm-commits]

https://github.com/preames approved this pull request.

LGTM

With the assembler changes from a while back, this should not be simply a heuristic.  

https://github.com/llvm/llvm-project/pull/80905