net: ena: Fix toeplitz initial hash value

On driver initialization, RSS hash initial value is set to zero,
instead of the default value. This happens because we pass NULL as
the RSS key parameter, which caused us to never initialize
the RSS hash value.

This patch fixes it by making sure the initial value is set, no matter
what the value of the RSS key is.

Fixes: 91a65b7d ("net: ena: fix potential crash when rxfh key is NULL")
Signed-off-by: Nati Koler <nkoler@amazon.com>
Signed-off-by: David Arinzon <darinzon@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>