net: qualcomm: rmnet: Convert the muxed endpoint to hlist

Rather than using a static array, use a hlist to store the muxed
endpoints and use the mux id to query the rmnet_device.
This is useful as usually very few mux ids are used.

CRs-Fixed: 2156182
Change-Id: I2a0c848d87d4f0b8d6d402405cb5d8d4258e162a
Cc: Dan Williams <dcbw@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Git-commit: 3352e6c45760fd6675468a35ef699ab94617cab4
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git


Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>