drm/amd/display: remove set but not used variable 'min_content'

Fixes gcc '-Wunused-but-set-variable' warning:

drivers/gpu/drm/amd/display/modules/color/color_gamma.c: In function build_freesync_hdr:
drivers/gpu/drm/amd/display/modules/color/color_gamma.c:830:20: warning: variable min_content set but not used [-Wunused-but-set-variable]

It is not used since commit 50575eb5 ("drm/amd/display:
Only use EETF when maxCL > max display")
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/modules/color/color_gamma.c

@@ -937,7 +937,6 @@ static bool build_freesync_hdr(struct pwl_float_data_ex *rgb_regamma,
 	struct fixed31_32 max_display;
 	struct fixed31_32 min_display;
 	struct fixed31_32 max_content;
-	struct fixed31_32 min_content;
 	struct fixed31_32 clip = dc_fixpt_one;
 	struct fixed31_32 output;
 	bool use_eetf = false;
@@ -951,7 +950,6 @@ static bool build_freesync_hdr(struct pwl_float_data_ex *rgb_regamma,
 	max_display = dc_fixpt_from_int(fs_params->max_display);
 	min_display = dc_fixpt_from_fraction(fs_params->min_display, 10000);
 	max_content = dc_fixpt_from_int(fs_params->max_content);
-	min_content = dc_fixpt_from_fraction(fs_params->min_content, 10000);
 	sdr_white_level = dc_fixpt_from_int(fs_params->sdr_white_level);
 
 	if (fs_params->min_display > 1000) // cap at 0.1 at the bottom