- When creating dma map, allocate at least one bounce page even if the

- When creating dma map, allocate at least one bounce page even if the
  max size of the dma tag is less than one page.
- alloc_bounce_pages() returns number of bounce pages that have been
  allocated, not error value.
- Increase MAX_BPAGES to 1024 to cooperate with modern devices.

Tested-by: Jörg Anslik <joerg@anslik.de>
Approved-by: dillon@