drm/i915: remove duplicate register #defines

Somehow a chunk of unused register defines ended up in the middle of
the PLL defines. They go back to the original kms merging.

The only used #define is SR01, move it to the register name together
with the other legacy vga stuff.

Reviewed-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>