drm/amd/display/dc/basics/fixpt31_32: Remove unused variable 'dc_fixpt_pi'

Fixes the following W=1 kernel build warning(s):

 drivers/gpu/drm/amd/amdgpu/../display/dc/basics/fixpt31_32.c:29:32: warning: ‘dc_fixpt_pi’ defined but not used [-Wunused-const-variable=]

Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: amd-gfx@lists.freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/basics/fixpt31_32.c

@@ -26,7 +26,6 @@
 #include "dm_services.h"
 #include "include/fixed31_32.h"
 
-static const struct fixed31_32 dc_fixpt_pi = { 13493037705LL };
 static const struct fixed31_32 dc_fixpt_two_pi = { 26986075409LL };
 static const struct fixed31_32 dc_fixpt_ln2 = { 2977044471LL };
 static const struct fixed31_32 dc_fixpt_ln2_div_2 = { 1488522236LL };