lib: add bitmap_{from,to}_arr64

lib: add bitmap_{from,to}_arr64

Manipulating 64-bit arrays with bitmap functions is potentially dangerous
because on 32-bit BE machines the order of halfwords doesn't match.
Another issue is that compiler may throw a warning about out-of-boundary
access.

This patch adds bitmap_{from,to}_arr64 functions in addition to existing
bitmap_{from,to}_arr32.

CC: Alexander Gordeev <[email protected]>
CC: Andy Shevchenko <[email protected]>
CC: Christian Borntraeger <[email protected]>
CC: Claudio Imbrenda <[email protected]>
CC: David Hildenbrand <[email protected]>
CC: Heiko Carstens <[email protected]>
CC: Janosch Frank <[email protected]>
CC: Rasmus Villemoes <[email protected]>
CC: Sven Schnelle <[email protected]>
CC: Vasily Gorbik <[email protected]>
Signed-off-by: Yury Norov <[email protected]>