bcma: add missing includes

kbuild found out that commit 804e27dee49e ("bcma: support bringing up
bus hosted on PCIe Gen 2") broke the build on m68k:

drivers/bcma/driver_pcie2.c: In function 'bcma_core_pcie2_up':
>> drivers/bcma/driver_pcie2.c:196:2: error: implicit declaration of function 'pcie_set_readrq' [-Werror\
=implicit-function-declaration]
err = pcie_set_readrq(dev, pcie2->reqsize);
^
cc1: some warnings being treated as errors

Reported-by: kbuild test robot <[e-mail]>
Signed-off-by: Rafał Miłecki <[e-mail]>
Signed-off-by: Kalle Valo <[e-mail]>

drivers/bcma/driver_pci_host.c

···
 
 #include "bcma_private.h"
 #include <linux/pci.h>
+#include <linux/slab.h>
 #include <linux/export.h>
 #include <linux/bcma/bcma.h>
 #include <asm/paccess.h>

drivers/bcma/driver_pcie2.c

···
 
 #include "bcma_private.h"
 #include <linux/bcma/bcma.h>
+#include <linux/pci.h>
 
 /**************************************************
  * R/W ops.