drm/amd/display: Prevent crash when disable stream

[Why]
Disabling stream encoder invokes a function that no longer exists.

[How]
Check if the function declaration is NULL in disable stream encoder.

Cc: Mario Limonciello <[email protected]>
Cc: Alex Deucher <[email protected]>
Cc: [email protected]
Reviewed-by: Charlene Liu <[email protected]>
Acked-by: Wayne Lin <[email protected]>
Signed-off-by: Chris Park <[email protected]>
Tested-by: Daniel Wheeler <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

0 files changed, 0 insertions, 0 deletions