drm/amd/display: fix transfer function passed to build_coefficients()

The default argument should be enum TRANSFER_FUNCTION_SRGB rather than
the current boolean value which improperly maps to
TRANSFER_FUNCTION_BT709.

Commit 9b3d76527f6e ("drm/amd/display: Revert adding degamma coefficients")
looks to have improperly reverted
commit d02097095916 ("drm/amd/display: Add regamma/degamma coefficients and set sRGB when TF is BT709")
replacing the enum value with a boolean value.

Cc: Krunoslav Kovac <[e-mail]>
Cc: Jaehyun Chung <[e-mail]>
Cc: Zeng Heng <[e-mail]>
Fixes: 9b3d76527f6e ("drm/amd/display: Revert adding degamma coefficients")
Reviewed-by: Harry Wentland <[e-mail]>
Signed-off-by: Alex Deucher <[e-mail]>

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

···
 	struct pwl_float_data_ex *rgb = rgb_regamma;
 	const struct hw_x_point *coord_x = coordinates_x;
 
-	build_coefficients(&coeff, true);
+	build_coefficients(&coeff, TRANSFER_FUNCTION_SRGB);
 
 	i = 0;
 	while (i != hw_points_num + 1) {