usb: gadget: tegra: set cpu normal in work context

usb: gadget: tegra: set cpu normal in work context

Once USB transfers are completed, set cpu frequency
to normal in work context.

Bug 1292315

Change-Id: I34e6f6d85f3be8be31e5d87a742894d0ca10f8bc
Signed-off-by: Rakesh Bodla <rbodla@nvidia.com>
Reviewed-on: http://git-master/r/231064
(cherry picked from commit c2b7bf3f3a0414ef0216e822fa9f5205d5b3075d)
Reviewed-on: http://git-master/r/240244
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Venkat Moganty <vmoganty@nvidia.com>