msm: synx: apis for clients to register bind operations

Provide apis for external clients to registers bind operations
with the synx driver. This enables registered external sync
fences to provide bind operation (equivalence) with synx obj.
This also eliminates synx driver dependency with external fence
implementations.

Change-Id: Ia417bc42d485906c4b805820595c6c9e05ee5877
Signed-off-by: Sumukh Hallymysore Ravindra <shallymy@codeaurora.org>