Revert "net: bcmgenet: Software reset EPHY after power on"

With commit f7d72996e222 ("net: bcmgenet: enable loopback during
UniMAC sw_reset") it is no longer necessary to force the software
reset of the internal EPHY before resetting the UniMAC to ensure a
clean reset.

Therefore this commit reverts commit 5dbebbb4

 ("net: bcmgenet:
Software reset EPHY after power on").

Signed-off-by: Doug Berger <opendmb@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>