i965: allow image_size on float images

This got missed because the piglit test only tested int images to avoid a
combinatiorial explosion of format, targets, stages and sizes which
takes more than 5 minutes to test on nvidia's driver.

This patch also drops the IMAGE_FUNCTION_AVAIL_ATOMIC which is not applicable
to the image_size codepath but was not hurting in any way.

Signed-off-by: Martin Peres <martin.peres@linux.intel.com>
Reviewed-by: Francisco Jerez <currojerez@riseup.net>

src/glsl/builtin_functions.cpp

@@ -2739,7 +2739,8 @@ builtin_builder::add_image_functions(bool glsl)
 
    add_image_function(glsl ? "imageSize" : "__intrinsic_image_size",
                       "__intrinsic_image_size",
-                      &builtin_builder::_image_size_prototype, 1, atom_flags);
+                      &builtin_builder::_image_size_prototype, 1,
+                      flags | IMAGE_FUNCTION_SUPPORTS_FLOAT_DATA_TYPE);
 }
 
 ir_variable *