drm/amd/display: Fix function banner for amdgpu_dm_psr_disable_all()

[WHY]
Incorrect function name in function banner.

[HOW]
Correct name and brief description.
Reviewed-by: Hersen Wu <hersenxs.wu@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Acked-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Roman Li <roman.li@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_psr.c

@@ -210,7 +210,7 @@ bool amdgpu_dm_psr_disable(struct dc_stream_state *stream)
 }
 
 /*
- * amdgpu_dm_psr_disable() - disable psr f/w
+ * amdgpu_dm_psr_disable_all() - disable psr f/w for all streams
  * if psr is enabled on any stream
  *
  * Return: true if success