md: remove typedefs: mirror_info_t -> struct mirror_info

Signed-off-by: NeilBrown <neilb@suse.de>

diff --cc drivers/md/raid1.c
Simple merge

diff --cc drivers/md/raid1.h
Simple merge

diff --cc drivers/md/raid10.c
Simple merge

diff --cc drivers/md/raid10.h
Simple merge