arm: mvebu: turris_omnia: fix eeprom/mcu device names

Commit c4bd12a7 ("i2c: mux: Generate longer i2c mux name") changed
the naming scheme of i2c devices within a mux. This broke references to
i2c@0 in the Turris Omnia board initialization code.

Signed-off-by: Pierre Bourdon <delroth@gmail.com>
Cc: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Signed-off-by: Stefan Roese <sr@denx.de>