Fix LayerScale ignoring init_values

[Ilya-Fradlin]

Previously, reset_parameters() set gamma to ones, ignoring init_values and effectively disabling LayerScale’s small-init behavior.

Now, gamma is initialized to init_values via nn.init.constant_ preserving the intended effect.

[rwightman]

@Ilya-Fradlin thanks, FYI I have quite a bit set of changes like/related to this to implement a two phase init, but will merge this one regardless. EDIT woops I cut that off... becuase there's a regression here, I removed a number of local 'LayerScale' impl that did not have this issue and used this central one which does have the problematic reset... was probably in my changes a month back.

[HuggingFaceDocBuilderDev]

The docs for this PR live here. All of your documentation changes will be reflected on that endpoint. The docs are available until 30 days after the last update.