misc: rt5501: revert amp init sequence changes

Perform proper mode switching in userspace instead.

Revert "rt5501: adjust amp value for wired headset and headphones"

This reverts commit 4f518aa1a6a43061680355b660cfdcec272630ad.

Revert "rt5501: Reduce gain to -6dB, turn additonal noise gate on"

This reverts commit 4cb1ab01e280809a3e5b38ab8c3a0396104777fb.

Change-Id: Ia06e6aeec536c9454a7858e8dd0c5b9b056f47a6