nir: handle double-precision in fabs, frsq and fsqrt
nir: handle double-precision in fabs, frsq and fsqrt

Reviewed-by: Matt Turner <789b315743a28dd066a4ba1459c35951c291d8a6@gmail.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler