util: fix 32 bpp patterns on big-endian

util: fix 32 bpp patterns on big-endian

DRM formats are defined to be little-endian, unless the
DRM_FORMAT_BIG_ENDIAN flag is set.  Hence writes of multi-byte pixel
values need to take endianness into account.

Introduce a swap32() helper to byteswap 32-bit values, and a
cpu_to_le32() helper to convert 32-bit values from CPU-endian to
little-endian, and use the latter in the various pattern fill functions
for 32-bit formats.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Pekka Paalanen <pekka.paalanen@collabora.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
---
v5:
  - Add Reviewed-by,

v4:
  - Use new HAVE_BIG_ENDIAN symbol,

v3:
  - Increase indentation after definition of cpu_to_le32(),

v2:
  - Add Acked-by,
  - Add swap32() intermediate helper,
  - Add __ARM_BIG_ENDIAN and __s390__.