We can't pass a string on the stack to request_region. As soon as we
leave the function that stack is gone and the string is lost. Let's
use the same string we identify the i2c_adapter with instead, it's
more simple, more consistent, and just works.

This is the second half of fix to bug #6445.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>