qca_7k: Replace old mail address

The company I2SE has been acquired a long time ago. Switch to
my private mail address before the I2SE account is deactivated.

Signed-off-by: Stefan Wahren <stefan.wahren@i2se.com>
Signed-off-by: Stefan Wahren <wahrenst@gmx.net>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>