board: gateworks: venice: delay before reading GSC EEPROM

Extensive testing has shown that at higher temperatures operating
without a GSC backup battery, the GSC needs a small delay after
releasing the I2C SDA/SCL pins before it is ready to handle I2C
requests.

Add a delay to avoid errors such as:
wait_for_sr_state: Arbitration lost sr=93 cr=80 state=2020
i2c_init_transfer: failed for chip 0x20 retry=0

Signed-off-by: Tim Harvey <tharvey@gateworks.com>