net: netcp: ethss: cleanup gbe_probe() and gbe_remove() functions

This patch clean up error handle code to use goto label properly. In some
cases, the code unnecessarily use goto instead of just returning the error
code.  Code also make explicit calls to devm_* APIs on error which is
not necessary. In the gbe_remove() also it makes similar calls which is
also unnecessary.

Also fix few checkpatch warnings

Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
Signed-off-by: David S. Miller <davem@davemloft.net>