[llvm] AMDGPU/GlobalISel: Implement RegBankLegalizeRules for amdgcn_log, amdgcn_rcp, and amdgcn_sqrt (PR #195099)

[Petar Avramovic via llvm-commits]

petar-avramovic wrote:

Still missing a lot of test coverage, some of existing test files have some cases, could add globalisel run line to some or write new one

https://github.com/llvm/llvm-project/pull/195099