serial: drop useless ctlr field

serial: drop useless ctlr field

The multi serial support has a "ctlr" field which almost no one uses,
but everyone is forced to set to useless strings.  So punt it.

Funny enough, the only code that actually reads this field (the mpc8xx
driver) has a typo where it meant to look for the SCC driver.  Fix it
while converting the check to use the name field.

Signed-off-by: Mike Frysinger <[email protected]>
CC: Heiko Schocher <[email protected]>
CC: Anatolij Gustschin <[email protected]>
CC: Tom Rix <[email protected]>
CC: Minkyu Kang <[email protected]>
CC: Craig Nauman <[email protected]>
CC: Marek Vasut <[email protected]>
CC: Prafulla Wadaskar <[email protected]>
CC: Mahavir Jain <[email protected]>