drm/amd/display: Rework context change check

Context change is all about streams; for this reason, this commit
renames context_changed to streams_changed. Additionally, to make this
function more flexible, this commit changes the function signature to
receive the stream array and the stream count as a parameter.

Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Co-developed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>