mhi: core: Only allow registration if channel is supported by endpoint.

Not all endpoints support all channels supported by MHI host. Only allow
clients to register if requested channel is supported by endpoint.

CRs-Fixed: 2053250
Change-Id: Ib4bd8d21b8f43d693da30b8fafe2cb9d2e128a17
Signed-off-by: Sujeev Dias <sdias@codeaurora.org>