net: qualcomm: rmnet: Fix leak in device creation failure

If the rmnet device creation fails in the newlink either while
registering with the physical device or after subsequent
operations, the rmnet endpoint information is never freed.

CRs-Fixed: 2156182
Change-Id: I23eedc5b2291cf21a249ad1089ab4cd9d6752281
Fixes: ceed73a2 ("drivers: net: ethernet: qualcomm: rmnet: Initial implementation")
Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>