net: dsa: mv88e6xxx: Cosmetic change spaces to tabs in dsa_switch_ops

All but 5 methods in dsa_swith_ops use tabs for indentation.

Change the 5 methods that break this rule.

Signed-off-by: Marek Behún <kabel@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>