staging: tidspbridge: remove gh_init() and gh_exit()

The gh module has a gh_init() and a gh_exit(), but they don't do
anything, they are just noops.

This patch removes these functions.

There is no functional changes.

Signed-off-by: Víctor Manuel Jáquez Leal <vjaquez@igalia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>