Fix minimum image size for cl_ext_image_requirements_info

Some new extension formats require the width to be a multiple
of 4 or 2 (see cl_ext_image_raw10_raw12).
Change has not functional impact as the affected image is only used
for generic queries.

Signed-off-by: John Kesapides <john.kesapides@arm.com>

test_conformance/images/kernel_read_write/test_cl_ext_image_buffer.hpp

@@ -48,8 +48,10 @@ static inline size_t get_format_size(cl_context context,
  cl_image_desc image_desc = { 0 };
  image_desc.image_type = imageType;
 
- /* Size 1 only to query element size */
- image_desc.image_width = 1;
+ /* We use a width of 4 to query element size, as this is
+ the smallest possible value that satisfies the requirements
+ of all image formats (including extensions). */
+ image_desc.image_width = 4;
  if (CL_MEM_OBJECT_IMAGE1D_BUFFER != imageType
  && CL_MEM_OBJECT_IMAGE1D != imageType)
  {