mhi: dev: satellite: driver clean-up

Clean-up debugfs hooks as feature is enabled by default and
remove unsupported subsystem entries no longer required.

CRs-Fixed: 2479799
Change-Id: I38b5f520918092a7174f59df8b8ed8b0bc7ed5a7
Acked-by: Bhaumik Vasav Bhatt <bbhatt@qti.qualcomm.com>
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>