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 <fengguang.wu@intel.com>
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
diff --git a/drivers/bcma/driver_pcie2.c b/drivers/bcma/driver_pcie2.c
index 4568bc7..b1a6e32 100644
--- a/drivers/bcma/driver_pcie2.c
+++ b/drivers/bcma/driver_pcie2.c
@@ -10,6 +10,7 @@
 
 #include "bcma_private.h"
 #include <linux/bcma/bcma.h>
+#include <linux/pci.h>
 
 /**************************************************
  * R/W ops.