py/test: Fix xilinx i2c eeprom test

py/test: Fix xilinx i2c eeprom test

By converting Zynq boards to generic configuration there is no longer
option to use marking like "@pytest.mark.boardspec("zynq_zc706")" to run
certain tests.
That's why change this code to look for device specification what to test.

Here is setup for zc706

env__i2c_eeprom_device_test = {
	"bus": 3,
	"eeprom_addr": 0x54,
}

Variable env__i2c_device_test_skip is completely removed because logic has
changed.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>
State: pending