net: ethernet: ti: am65-cpsw: Fix error handling in am65_cpsw_nuss_common_open()

k3_udma_glue_enable_rx/tx_chn returns error code on failure.
Bail out on error while enabling TX/RX channel.

In the error path, clean up the RX descriptors and SKBs.
Get rid of kmemleak_not_leak() as it seems unnecessary now.

Fixes: 93a76530 ("net: ethernet: ti: introduce am65x/j721e gigabit eth subsystem driver")
Signed-off-by: Roger Quadros <rogerq@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>