pcmcia: simplify rsrc_nonstatic attributes

Simplify sysfs attribute registration for sockets without static
resource mappings by using an attribute_group.  This shrinks object
size a bit:  use loops in sysfs code, but have more data.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>