In trying to build on a RHEL6.3 I ran into several build issues that are
addressed in this patch.

The first is that xtables_merge_options only has 3 parameters.  It appears
this is how this code was originally.  As such for the case where the version
is less than 6 I am assuming it would be correct to maintain the original
setup that only had 3 parameters being passed instead of 4.

I also ran into an issue with the define for __ALIGN_KERNEL not being present.
I believe this may be due to the fact that __ALIGN_KERNEL was moved into a
separate header from ALIGN after the UAPI changes.  In order to just cover all
of the bases I have moved the main definition for the macros into
__ALIGN_KERNEL_MASK and __ALIGN_KERNEL and if ALIGN is also needed then it is
just a direct redefine to __ALIGN_KERNEL.

Cc: Hasan Chowdhury <shemonc@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>