Staging: rtl8192e: off by one in rtl8192_get_channel_map()

COUNTRY_CODE_MAX is not a valid country code.  We're off by one here.
This gets passed to Dot11d_Channelmap() where it's used as an offset
into the ChannelPlan[] array.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>