net: airoha: Fix a copy and paste bug in probe()

net: airoha: Fix a copy and paste bug in probe()

This code has a copy and paste bug where it accidentally checks "if (err)"
instead of checking if "xsi_rsts" is NULL.  Also, as a free bonus, I
changed the allocation from kzalloc() to  kcalloc() which is a kernel
hardening measure to protect against integer overflows.

Fixes: 5863b4e065e2 ("net: airoha: Add airoha_eth_soc_data struct")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Acked-by: Lorenzo Bianconi <lorenzo@kernel.org>
Link: https://patch.msgid.link/aPtht6y5DRokn9zv@stanley.mountain
Signed-off-by: Jakub Kicinski <kuba@kernel.org>