amdgcn: Consolidate atomic minmax helpers

Removes most overrides
Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>
Reviewer: Aaron Watry

llvm-svn: 347665
GitOrigin-RevId: 3a7e8e77e6826c591e923fcfbcb1acccc2aeb305
11 files changed