i965: Remove duplicate copy of is_scalar_shader_stage().

Jason open coded this in 60befc63 when cleaning up some ugly code;
using our existing helper tidies it up a bit more.

v2: Drop inline (suggested by Matt).

Signed-off-by: Kenneth Graunke <kenneth@whitecape.org>
Reviewed-by: Jason Ekstrand <jason.ekstrand@intel.com>
Reviewed-by: Matt Turner <mattst88@gmail.com>
1 file changed