This partially reverts 39f3d72b72, which changes almost all targets to
use __builtin_elementwise_fma.
The same revert was done for clspv in 1d719edd99.
Restore __clc_runtime_has_hw_fma32 so that Mesa can dynamically change
its behavior to enable native fma for specific hardware.
Fixes#198542
767f01e091