tests: i2c: i2c_target_api: fix b_u585i_iot02a test

The b_u585i_iot02a platform already has an 'eeprom0' node in the default
devicetree. Delete the default node so that the overlay can define the
nodes needed for the test.

Signed-off-by: Bram Vlerick <bram.vlerick@openpixelsystems.org>