drm/i915: Rewrite ABS_DIFF() in a safer manner
drm/i915: Rewrite ABS_DIFF() in a safer manner

The new version of the macro does a few things better:
  - protect the arguments,
  - only evaluate the arguments once,
  - check that the arguments are of the same type,

Change LC_FREQ_2K to be a unsigned 64bit constant and removed the '()'
from the caller as a result.

Signed-off-by: Damien Lespiau <64bd3cb94f359c1a3ce68dae5e26b40578526277@intel.com>
Reviewed-by: Jani Nikula <ba783f3beccaedfda693f41a15407d612a629408@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs,KristFoundation/Programs