net: qualcomm: rmnet: Move the device creation log

The current log is not very useful as it does not log the device
name since it it is prior to registration -

(unnamed net_device) (uninitialized): Setting up device

Modify to log after the device registration -

rmnet1: rmnet dev created

Signed-off-by: Subash Abhinov Kasiviswanathan <subashab@codeaurora.org>
Signed-off-by: David S. Miller <davem@davemloft.net>