i965/fs: fix is_copy_payload() for doubles
i965/fs: fix is_copy_payload() for doubles

v2 (Sam):
- LOAD_PAYLOAD treats each header source as a 32B block
  regardless of the datatype. Drop the change (Curro)

Reviewed-by: Kenneth Graunke <bd2562f754ec92342f93f61c25d731e290a2ffa8@whitecape.org>
Reviewed-by: Jordan Justen <a79006884ba9cf5f4f7fcbb92a15b208780d8c97@intel.com>

metora/MesaGLSLCompiler,metora/MesaGLSLCompiler,metora/MesaGLSLCompiler