compat: backport fb_info->skip_vt_switch using a static inline

compat: backport fb_info->skip_vt_switch using a static inline

Commit 3cf2667 as of next-20130301 extended the struct fb_info
with a skip_vt_switch to allow drivers to skip the VT switch
at suspend/resume time. For older kernels we can skip this
as all this switch does is call pm_vt_switch_required() with true
or false depending on this new flag and later
pm_vt_switch_unregister() would not have been made.

compat-drivers was backporting this using #ifdef's but by
integrating a static inline we'd reduce the number of lines
to backport to just 1 line replacement. This would be something
like:

  -       info->skip_vt_switch = true;
  +       fb_enable_skip_vt_switch(info);

For kernels >= 3.10 we'd set the attribute as we do upstream,
for older kernels this would be a no-op.

If this static inline would have been added upstream it would
have meant this collateral evolution would require just adding
a no-op static inline to backport, and no changes as the above
example hunk for every driver that requires the change.

If this static inline ends up upstream *now* it means we do *not*
require the type of hunk above for every driver that requires
the change.

All the code would be left intact !

This is a linux-next 'data structure element collateral evolution'.

Cc: cocci@systeme.lip6.fr
Cc: backports@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Julia Lawall <julia.lawall@lip6.fr>
Cc: Rodrigo Vivi <rodrigo.vivi@gmail.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Luis R. Rodriguez <mcgrof@do-not-panic.com>