bug #40569: define BOD_CONTROL_REG based on BODCR or MCUCR so that sleep_bod_disable macro can use that instead of MCUCR always.

git-svn-id: http://svn.savannah.nongnu.org/svn/avr-libc/trunk@2433 1084037a-409f-4a99-8160-1a4b3577d4c1