As it's aligned to 16, all structures that contain it should be
also aligned to 16. In the kernel there is no such align as
there two separate definitions of i387_fxsave_struct:
one for ia32 and another for x86_64.
Fixes newly introduced align warning in gcc-8.1:
In file included from compel/include/uapi/compel/asm/sigframe.h:7,
                 from compel/plugins/std/infect.c:13:
compel/include/uapi/compel/asm/fpu.h:89:1: error: alignment 1 of 'struct xsave_struct_ia32' is less than 16 [-Werror=packed-not-aligned]
 } __packed;
 ^

It doesn't change the current align of the struct, as containing
structures are __packed and it aligned already *by fact*.
It only affects the function users of the struct's local variables:
now they lay aligned on a stack.
Signed-off-by: Dmitry Safonov <dima@arista.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>