Use built-in animation fading instead of a separate part

As the boot animation now supports fading out transition
without introduction of that step it is reasonable to use that
and make the transitioning smoother and the animation structure simpler.

Structural changes:
| parts        | changes                                        |
| ------------ | ---------------------------------------------- |
| part0..part3 | no changes                                     |
| part4        | p 0 0 part4 => f 0 0 part4 10                  |
| part5        | removed - 10 frames are faded out in the part4 |

Bug: 172901134

Test: Flash and boot, observe the animation looks similar in the end
but fading while continuing playing

Change-Id: I7dfe207701bbb57c764135ebf89a91717293f3ba
Merged-In: I7dfe207701bbb57c764135ebf89a91717293f3ba
1 file changed