i2c: brcmstb: Remove superfluous size check

The driver transfer to a message with NOACK always in any size.
If client (eg. EDID segment point message) needs NOACK condition, it can
use I2C_M_IGNORE_NAK flag.

Signed-off-by: Jaedon Shin <jaedon.shin@gmail.com>
Acked-by: Kamal Dasu <kdasu.kdev@gmail.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>