[PATCH 1/1] r600: Use llvm intrinsic to read work dimension information

v2: Fix function declration
    Add range metadata to r600 implementation

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

v2: Fix function declaration
    Add range metadata to r600 implementation
v3: change prefix to AMDGPU

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

v2: Fix function declaration
    Add range metadata to r600 implementation
v3: change prefix to AMDGPU

Signed-off-by: Jan Vesely <jan.vesely@rutgers.edu>

LGTM.