drm: Fix DP_TEST_COUNT_MASK
drm: Fix DP_TEST_COUNT_MASK

By Vesa's DP 1.2 Spec this counter has 4 bits [3:0].

This mask is wrong since when the counter was introduced by myself
on commit ad9dc91b6e21266bfc6f466db4b95e10211f31ee
Author: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Date:   Tue Sep 16 19:18:12 2014 -0400

    drm/i915: Fix Sink CRC

Signed-off-by: Rodrigo Vivi <f714145d6ee82178e54021e0c168f56d17b53c9c@intel.com>
Reviewed-by: Sivakumar Thulasimani <afd63e03aa0ce25d3ef045af65dcdb25f653ca00@intel.com>
Signed-off-by: Daniel Vetter <c1b6782c4af8f0673da8923a0702a1832e5940f4@ffwll.ch>

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