USB: cp210x: Remove double usb_control_msg from cp210x_set_config

This patch removes a double usb_control_msg that sets the cp210x
configuration registers a second time when calling cp210x_set_config.
For data sizes >2 the second write gets corrupted.
The patch has been created against 2.6.34-rc1, but all cp210x driver
revisions are affected.

Signed-off-by: Michael Brunner <mibru@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>