lib: bitmap: fix the duplicated comments on bitmap_to_arr64()

Thanks to the recent commit 0a97953f ("lib: add
bitmap_{from,to}_arr64") now we can directly convert a U64 value into a
bitmap and vice verse.

However when checking the header there is duplicated helper for
bitmap_to_arr64(), but no bitmap_from_arr64().

Just fix the copy-n-paste error.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

include/linux/bitmap.h

@@ -71,9 +71,9 @@ struct device;
  *  bitmap_release_region(bitmap, pos, order)   Free specified bit region
  *  bitmap_allocate_region(bitmap, pos, order)  Allocate specified bit region
  *  bitmap_from_arr32(dst, buf, nbits)          Copy nbits from u32[] buf to dst
+ *  bitmap_from_arr64(dst, buf, nbits)          Copy nbits from u64[] buf to dst
  *  bitmap_to_arr32(buf, src, nbits)            Copy nbits from buf to u32[] dst
  *  bitmap_to_arr64(buf, src, nbits)            Copy nbits from buf to u64[] dst
- *  bitmap_to_arr64(buf, src, nbits)            Copy nbits from buf to u64[] dst
  *  bitmap_get_value8(map, start)               Get 8bit value from map at start
  *  bitmap_set_value8(map, value, start)        Set 8bit value to map at start
  *