pcmcia: add missing include for new pci resource handler

The recently added rsrc_pci.c file calls pci_bus_alloc_resource without
including the header file that declares it, and that sometimes causes
a build warning on ARM:

drivers/pcmcia/rsrc_pci.c: In function 'find_io_region':
drivers/pcmcia/rsrc_pci.c:40:2: error: implicit declaration of function 'pci_bus_alloc_resource' [-Werror=implicit-function-declaration]

This adds the missing include statement.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: 02b03846 ("pcmcia: add a new resource manager for non ISA systems")
Acked-by: Alan Cox <alan@linux.intel.com>
Reported-by: Jim Davis <jim.epost@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/pcmcia/rsrc_pci.c

 #include <linux/slab.h>
 #include <linux/module.h>
 #include <linux/kernel.h>
+#include <linux/pci.h>
 
 #include <pcmcia/ss.h>
 #include <pcmcia/cistpl.h>