SF: clamp alpha value instead of error

SF tests expect that invalid alpha values
will be clamped instead of returning failure.

Test: atest SurfaceFlinger_test:SurfaceFlinger_test
Bug: 274213741
Merged-In: I1318f21c21ec9b3fe9577ac3b9f32605e7f7f13a
Change-Id: I1318f21c21ec9b3fe9577ac3b9f32605e7f7f13a
(cherry picked from commit 24d0b2a19705cc64933bb6dfaf7147207a64e607)
1 file changed