bgmac: fix *initial* chip reset to support BCM5358

bgmac: fix *initial* chip reset to support BCM5358

While bringing hardware up we should perform a full reset including the
switch bit (BGMAC_BCMA_IOCTL_SW_RESET aka SICF_SWRST). It's what
specification says and what reference driver does.

This seems to be critical for the BCM5358. Without this hardware doesn't
get initialized properly and doesn't seem to transmit or receive any
packets.

Originally bgmac was calling bgmac_chip_reset() before setting
"has_robosw" property which resulted in expected behaviour. That has
changed as a side effect of adding platform device support which
regressed BCM5358 support.

Fixes: f6a95a24957a ("net: ethernet: bgmac: Add platform device support")
Cc: Jon Mason <jdmason@kudzu.us>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20230227091156.19509-1-zajec5@gmail.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>