i2c: eg20t: use NULL instead of 0

sparse rightfully says:
drivers/i2c/busses/i2c-eg20t.c:990:59: warning: Using plain integer as NULL pointer

Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>
Cc: Tomoya MORINAGA <tomoya.rohm@gmail.com>
1 file changed