sbull: fix compiling errors

root cause commits in linux-stable:
commit 0eb5afb3bae69a18bb4a8dbcbd361c4403fb54cd
Author: Zhao Hongjiang <zhaohongjiang@huawei.com>
Date:   Mon Jul 8 15:22:50 2013 +0800

    xtensa: remove the second argument of __bio_kmap_atomic()

    kmap_atomic allows only one argument now, just remove the unused 'kmtype'.

commit 3e4d3af501cccdc8a8cca41bdbe57d54ad7e7e73
Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date:   Tue Oct 26 14:21:51 2010 -0700

    mm: stack based kmap_atomic()

    Keep the current interface but ignore the KM_type and use a stack based
    approach.

    The advantage is that we get rid of crappy code like:

    	#define __KM_PTE			\
    		(in_nmi() ? KM_NMI_PTE : 	\
    		 in_irq() ? KM_IRQ_PTE :	\
    		 KM_PTE0)

    and in general can stop worrying about what context we're in and what kmap
    slots might be appropriate for that.

    The downside is that FRV kmap_atomic() gets more expensive.

    For now we use a CPP trick suggested by Andrew:

      #define kmap_atomic(page, args...) __kmap_atomic(page)

    to avoid having to touch all kmap_atomic() users in a single patch.

    [ not compiled on:
      - mn10300: the arch doesn't actually build with highmem to begin with ]

commit db2a144bedd58b3dcf19950c2f476c58c9f39d18
Author: Al Viro <viro@zeniv.linux.org.uk>
Date:   Sun May 5 21:52:57 2013 -0400

    block_device_operations->release() should return void

    The value passed is 0 in all but "it can never happen" cases (and those
    only in a couple of drivers) *and* it would've been lost on the way
    out anyway, even if something tried to pass something meaningful.
    Just don't bother.
scull: fix compiling errors when CONFIG_ UIDGID_STRICT_TYPE_CHECKS=y