Bluetooth: btintel_pcie: Fix warning reported by sparse

Fix sparse error.

Fixes: c2b636b ("Bluetooth: btintel_pcie: Add support for PCIe transport")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202405100654.0djvoryZ-lkp@intel.com/
Signed-off-by: Kiran K <kiran.k@intel.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

drivers/bluetooth/btintel_pcie.c

@@ -670,7 +670,7 @@ struct btintel_pcie_causes_list {
 	u8 cause_num;
 };
 
-struct btintel_pcie_causes_list causes_list[] = {
+static struct btintel_pcie_causes_list causes_list[] = {
 	{ BTINTEL_PCIE_MSIX_FH_INT_CAUSES_0,	BTINTEL_PCIE_CSR_MSIX_FH_INT_MASK,	0x00 },
 	{ BTINTEL_PCIE_MSIX_FH_INT_CAUSES_1,	BTINTEL_PCIE_CSR_MSIX_FH_INT_MASK,	0x01 },
 	{ BTINTEL_PCIE_MSIX_HW_INT_CAUSES_GP0, BTINTEL_PCIE_CSR_MSIX_HW_INT_MASK,	0x20 },