drm/i915: x86 always has writeq. Add I915_READ64 for symmetry.

i386 has inline code for writeq and readq, so just use those instead of ugly
macros which evaluate arguments multiple times.

Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
1 file changed