drm/amd/display: Conversion to bool not necessary

A logical evaluation already results in bool. There is no need for using
a ternary operator based evaluation and bool conversion of the outcome.
Issue identified using boolconv.cocci Coccinelle semantic patch.
This was also reported by the Kernel Test Robot. Hence

Fixes: 473683a0 ("drm/amd/display: Create a file dedicated for CRTC")

Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Deepak R Varma <drv@mailo.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>