drm/amd/display: Remove redundant braces in 'amdgpu_dm_crtc_notify_ta_to_read()'

Adhere to Linux kernel coding style.

Reported by checkpatch:

WARNING: braces {} are not necessary for single statement blocks

Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>