pcmcia: silence section mismatch warnings from class_interface variables

pcmcia: silence section mismatch warnings from class_interface variables

Silence the following warnings:
WARNING: drivers/pcmcia/built-in.o(.data+0x6e8): Section mismatch in reference from the variable pcmcia_bus_interface to the function .devinit.text:pcmcia_bus_add_socket()
WARNING: drivers/pcmcia/built-in.o(.data+0xa88): Section mismatch in reference from the variable pccard_rsrc_interface to the function .devinit.text:pccard_sysfs_add_rsrc()
WARNING: drivers/pcmcia/built-in.o(.data+0xa90): Section mismatch in reference from the variable pccard_rsrc_interface to the function .devexit.text:pccard_sysfs_remove_rsrc()

The variables of type class_interface contains references
to __devinit and __devexit functions which is OK.
Silence warnings by annotating the variables with __refdata.

Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Cc: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>