i2c: i2c-nct6775: fix -Wimplicit-fallthrough
Created by: solbjorn
Depending on a compiler, case I2C_SMBUS_BYTE_DATA
can trigger -Wimplicit-fallthrough / unannotated fallthrough as it doesn't mention it anyhow.
Add a fallthrough
attribute to silence this.
Fixes: 480fefb8 ("i2c: busses: Add SMBus capability to work with OpenRGB driver control")