net: mellanox: mlxbf_gige: Fix skb_panic splat under memory pressure

Do skb_put() after a new skb has been successfully allocated otherwise
the reused skb leads to skb_panics or incorrect packet sizes.

Fixes: f92e1869

 ("Add Mellanox BlueField Gigabit Ethernet driver")
Signed-off-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230524194908.147145-1-tbogendoerfer@suse.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>