ehea: Use the standard logging functions

Remove ehea_error, ehea_info and ehea_debug macros.
Use pr_fmt, pr_<level>, netdev_<level> and netif_<level> as appropriate.
Fix messages to use trailing "\n", some messages had an extra one
as the old ehea_<level> macros added a trailing "\n".
Coalesced long format strings.

Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Breno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>