init/do_mounts_md.c: remove duplicated #include

Removed duplicated #include <linux/delay.h> in init/do_mounts_md.c.

The same compile error ("error: implicit declaration of function
'msleep'") got fixed twice:

 - f8b77d39 ("init/do_mounts_md.c:
   msleep compile fix")

 - 73b4a24f

 ("init/do_mounts_md.c must
   #include <linux/delay.h>")

by people adding the <linux/delay.h> include in two slightly different
places.  Andrew's quilt scripts happily ignore the fuzz, and will
re-apply the patch even though they had conflicts.

Signed-off-by: Huang Weiyi <weiyi.huang@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>