Add support for SCCB by implementing I2C_M_IGNORE_NAK and I2C_M_STOP
flags and advertising functionality flag I2C_FUNC_PROTOCOL_MANGLING.

Also fixed missing functionality flag I2C_FUNC_NOSTART.

Signed-off-by: Petr Cvek <petr.cvek@tul.cz>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>