[ewg] [PULL][OFED 3.18] 7.1 compat patches

[Marciniszyn, Mike]

Vlad,

In the process of testing qib build on RHEL7.1, we needed to fix some underlying compat issues.

Once compat builds, qib appears to build without issue on these kernels:
RHEL7 kernel: 3.10.0-123.el7.x86_64
RHEL7.1 kernel: 3.10.0-229.el7.x86_64 (RC 2)

These fixes are:
1. Fix a warning introduced by prior work.
2. Added conditionally defined smp_mb__before_clear_bit().   RHEL7.1 <asm/bitops.h> no longer provides the define in all cases.
3. Detect reinit_completion().   RHEL7.1 now defines this in its native headers.

I realize that #2 and #3 might have already been done by someone else.

The <asm/bitops.h> work  in compat really needs some more attention.   

I suspect that the compat version of <asm/bitops.h> really should be <linux/bitops.h> with autoconf driven ifdefs or other ifdefs for the macros.

Please pull from these fixes from ~mmarciniszyn/scm/new_ofed/compat from the for-ofed-3.18 branch:

commit 70bfc3152e7efb47278b80fd8bebed3d639b9c8a
Author: Mike Marciniszyn <mike.marciniszyn at intel.com>
Date:   Wed Mar 4 11:57:49 2015 -0500

    compat: determine if reinit_completion() is present

    Use HAVE_REINIT_COMPLETION to avoid duplicate definition.

    Signed-off-by: Mike Marciniszyn <mike.marciniszyn at intel.com>

commit 0689335320e4aab4b5fe949143e103688c901c03
Author: Mike Marciniszyn <mike.marciniszyn at intel.com>
Date:   Wed Mar 4 11:37:59 2015 -0500

    compat: add smp_mb__before_clear_bit as necessary

    RHEL7.1 no longer has the above macro in <asm/bitops.h>.

    Add it in the compat version of <linux/bitops> as if
    <asm/bitops.h> had provided it.

    This really include probably needs to be reworked using
    the autoconf stuff.

    Signed-off-by: Mike Marciniszyn <mike.marciniszyn at intel.com>

commit 4f7837df4805267af03a6655b44a7f5c3f7f1891
Author: Mike Marciniszyn <mike.marciniszyn at intel.com>
Date:   Wed Mar 4 12:30:44 2015 -0500

    Correct HAVE_PCI_DEV_PCIE_MPSS spelling

    Commit fef932831471 ("autoconf options for qib driver for RHEL 6.6)
    introduced a build warning because of a spelling error.

    Signed-off-by: Mike Marciniszyn <mike.marciniszyn at intel.com>