i2c-mpc: use __devinit[data] for initialization functions and data

"__devinit[data]" has not yet been used for all initialization functions
and data. To avoid truncating lines, the struct "mpc_i2c_match_data" has
been renamed to "mpc_i2c_data", which is even the better name.

Signed-off-by: Wolfgang Grandegger <wg@denx.de>
Tested-by: Wolfram Sang <w.sang@pengutronix.de>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>