omnia-eeprom: Mark it nonshared

omnia-eeprom: Mark it nonshared

This tool was build in the phase 2 build, there the
TARGET_mvebu_cortexa9_DEVICE_cznic_turris-omnia dependecy was probably
not meat. Mark it as non shared to build it together with the target
where this option is set.

Signed-off-by: Hauke Mehrtens <hauke@hauke-m.de>
Link: https://github.com/openwrt/openwrt/pull/16975
Signed-off-by: Robert Marko <robimarko@gmail.com>
(cherry picked from commit 371e7bef4046fb3992ecfb92b5b741c22fa3ade6)
Link: https://github.com/openwrt/openwrt/pull/17097
Signed-off-by: Petr Štetiar <ynezz@true.cz>