include/linux/dma-mapping.h: remove DMA_xxBIT_MASK macros

git grep shows there are no users in tree, so we can remove them safely.

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Acked-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>